TH 

7222 


SB    bbl 


VENTILATION 


FOR 


DWELLINGS 


RURAL  SCHOOLS 


AND  STABLES 


KING 


Jfo, 


UNIVERSITY  FARM 


TH7222 


VENTILATION 


FOR 


DWELLINGS,  RURAL  SCHOOLS 
AND  STABLES 


BY 


F.    H.    KING 

Formerly  Professor  of  Agricultural  Physics  in  the  University  of  Wis- 

,consin.     Author  of  ' '  The  Soil; ' '    '  'Irrigation  and  Drainage; ' ' 

'  'Physics  of  Agriculture. 


MADISON,    WIS. 

Published  by    the   Author 

1908 


COPYRIGHT,  1908 
BY  F.  H.    KING. 
All  rights  reserved. 


PHYSICS   OF   AGRICULTURE 

By  F.  H.  KING 

Professor  of  Agricultural  Physics  in  the  University  of  Wisconsin,  1888-1901 ; 
Chief  of  the  Division  of  Soil  Management,  U.  S.  Department  of  Agricul- 
ture, 1901-1904. 

Author    of    "The    Soil."    1895;    "Irrigation    and    Drainage,"    1899:    "Tillage.    Its 
Philosophy    and    Practice,"    "The    Necessity    and    Practice   of    Drainage,"    in 
Cyclopedia    of    American    Agriculture,    1907  ;    "Drainage"    and    "Irrigation," 
in  The  Standard  Cyclopedia  of  Modern  Agriculture,  (British),  1908. 
Fourth   Edition,    604    pages,    71/£xf>iXj    inches,    170  illustrations. 
Published  by  the  author,  Madison,  Wis.     Price  $1.75 


CONTENTS 

Introduction     6-48 

SOIL  PHYSICS 

Nature,   Origin   and    Waste   of   Soils 49-68 

Chemical  and  Mineral  Nature  of  Soils 69-91 

Soluble  Salts  in   Field   Soils 92-107 

Physical  Nature  of  Soils 108-128 

Soil   Moisture    129-141 

Physics  of  Plant   Breathing  and   Root  Action 142-157 

Movements    of    Soil    Moisture 158-203 

Relation   of  Air  to   Soil ' 204-211 

Soil    Temperature     212-222 

Objects,   Methods  and   Implements  of  Tillage 223-254 

GROUND  WATER,  WELLS  AND  FARM  DRAINAGE 

Movements  of  Ground   Water 255-274 

Farm    Wells    275-285 

Principles   of   Farm   Drainage 286-310 

Practice    of    Underdrainage 311-328 

PRINCIPLES   OF   RURAL   ARCHITECTURE 

Strength    of    Materials 329-342 

Warmth,    Light    and    Ventilation 343-365 

Principles    of    Construction 366-393 

Construction    of     Silos 394-427 

FARM   MECHANICS 

Principles  of  Draft 428-443 

Construction   and  Maintenance  of  Country  Roads 444-485 

Farm   Motors    486-537 

Farm   Machinery    538-553 

PRINCIPLES   OF   WEATHER    FORECASTING 

The    Atmosphere    554-560 

Movements  of  the  Atmosphere 561-577 

Weather    Changes    578-592 

"All  in  all,  this  is  the  greatest  and  best  collection  of  modern  agricultural 
scientific  facts,  practically  applied,  that  we  have  seen.  Anyone,  whether  he  be 
a  farmer  or  not  or  whether  he  bfe  a  student  In  a  college  or  an  old  man  in  the 
field,  can  learn  a  great  deal  here.  It  is  a  mine  of  correct  information.  We 

shall  value  It  highly  as?  a  work  of  reference." — Ohio  Farmer,  March  27,  1902. 


CONTENTS 


INTRODUCTION  (pages  1-44) 

PAGES 

NATURE'S  PROVISION  FOR  VENTILATION  OF  BODY  TISSUES 3-  8 

AMOUNT  OF  AIR  REQUIRED  FOR  A  DAILY  RATION 8-11 

AIR  ONCE  BREATHED  HAS  LOST  MUCH  OF  ITS  SUSTAINING  POWER 11-  17 

A  CONTINUOUS  FLOW  OF  AIR  is  NECESSARY 17-  19 

FRESH  AIR  SUPPLY  CERTAIN  TO  BE  INADEQUATE  AT  TIMES  IF  DEFINITE 

PROVISION  FOR  IT  is  NOT  MADE 19-  24 

SERIOUS  EFFECTS  FOLLOW  INSUFFICIENT  VENTILATION 24-31 

VOLUME  OF  AIR  WHICH  SHOULD  MOVE  CONTINUOUSLY  THROUGH 

DWELINGS  AND  STABLES 31-45 


PRINCIPLES  OF  VENTILATION  (pages  45-75) 

POWER  USED  IN  VENTILATION 46-  64 

MAINTENANCE  OF  TEMPERATURE  WITH  AMPLE  VENTILATION 64-75 

PRACTICE  OF  VENTILATION  (pages  76-126) 

BEST  ROOM  AND  STABLE  TEMPERATURE 76-78 

LIGHT  FOR  DWELLINGS  AND  STABLES 78-  88 

VENTILATION  OF  DWELLINGS 88-102 

Ventilation  of  Houses  Already  Built 90-94 

Warming  and  Ventilation  of  New  and  Remodeled  Houses 94-102 

HEATING  AND  VENTILATION  OF  RURAL  SCHOOL-HOUSES  AND  CHURCHES102-106 

STABLE  VENTILATION 107-126 

Ventilation  of  Dairy  Stables 109-120 

Ventilation  for  Swine  and  Sheep 120-123 

Ventilation  of  Poultry  Houses . .  .123-126 


PREFACE 


In  the  preparation  of  this  brief  treatise  the  aim  has  been 
to  reach  parents,  teachers  and  school  officers  of  rural  and 
other  elementary  schools,  and  the  owners  and  caretakers  of 
all  classes  of  live  stock,  and  lay  before  them  the  founda- 
tion facts  and  principles  underlying  the  growing  and  im- 
perative demand  for  a  more  nearly  adequate  supply  of 
pure  air  than  is  being  continuously  maintained  in  the  vast 
majority  of  homes,  offices  and  stables  today. 

In  presenting  the  subject  the  effort  has  been  to  make 
the  treatment  suggestive  to  teachers,  introducing  lines  of 
simple  experimentation  and  arithmetical  calculations,  so 
that  they  may  more  surely  enlist  the  attention  and  coop- 
eration of  their  community  in  the  immediately  practical 
aspects  of  the  subject.  It  is  hoped,  too,  that  all  owners 
and  caretakers  of  live  stock  will  find  the  treatment  of 
stable  ventilation  sufficiently  explicit  and  illustrative  to 
enable'  them  to  readily  and  effectively  solve  their  own  prob- 
lems. 

In  applying  the  principles  used  in  stable  ventilation  to 
dwellings,  offices  and  school-houses,  where  mechanical  ap- 
pliances or  hot  air  furnaces  are  not  used,  we  are  convinced 
that  there  are  no  practical  difficulties  in  the  way  and  that 
when  such  a  system  of  ventilation  is  combined  with  the 
warming  as  suggested  it  will  be  found  thoroughly  efficient. 
In  the  effort  to  be  brief,  and  yet  have  the  presentation 
sufficiently  fundamental  and  explicit  so  as  not  to  mislead, 
it  has  been  necessary,  in  the  treatment  of  dwellings  and 
schools,  to  omit  details,,  yet  it  is  hoped  enough  has  been 
given  so  that  with  the  aid  of  builders  and  .local  architects 
installations  may  be  readily  made. 

F.  H.  KING. 

Madison,  Wisconsin. 

Nov.  23,  1908. 


"And  did  it  occur  to  you  that  here,  too,  was  another  bellows  feeding 
air  into  another  forge,  'keeping  the  fire  of  life  aglow  and  timing  Its 
Intensity  to  the  work  to  be  done?" — Page  1. 


INTRODUCTION 


Have  you  stood  in  a  smithy's  door  and  watched  the  cold 
bar  of  iron  mount  by  quick  steps  to  a  white  heat  as  the 
strong  arm  on  the  bellows  compelled  fresh  air  through  the 
bed  of  coals  on  the  forge  ?  Did  you  reflect  that  that  inter- 
mittent air  current  contributed  more  pounds  avoirdupois  to 
the  generation  of  the  heat  than  did  the  coal,  in  the  ratio  of 
about  8  to  3?  Did  you  note  the  capacity  of  the  huge  bel- 
lows, the  powerful  lever  with  which  it  was  worked,  the 
length  of  the  strokes  and  the  weight  which  the  smith  threw 
onto  the  bellows  to  feed  sufficient  air  to  his  forge  ?  Did  you 
note  the  rythmical  rise  and  fall  of  the  smith's  deep  chest 
as  he  moved  about  his  work?  How  the  heaving  quickened 
and  deepened  as  the  blows  from  the  hammer  fell  more 
swiftly  and  with  greater  force  upon  the  shaping  piece? 
And  did  it  occur  to  you  that  here,  too,  was  another  bellows, 
feeding  air  into  another  forge,  keeping  the  fire  of  life  aglow 
and  timing  its  intensity  to  the  work  to  be  done  ? 

Did  you  observe  how  thoroughly  the  smith  kept  drawing 
up  over  his  fire  a  blanket  of  cinders  and  coal,  that  the  heat 
should  be  retained  where  the  work  was  being  done  and  that 
as  little  as  possible  should  be  wasted  ?  And  did  you  realize 
how  much  more  this  greater  economy  made  the  action  of  the 
bellows  necessary  to  carry  sufficient  air  to  the  exact  place 
where  it  must  be  used  ?  And  do  you  realize  with  what  con- 
sumate  economy  all  the  forges  of  life,  whether  of  man, 
beast,  bird  or  bee,  have  been  housed  in  from  the  cold  and 
are  continuously  fanned,  whether  waking  or  asleep,  by  au- 
tomatic bellows,  thus  generating  the  maximum  of  energy 
with  the  minimum  of  fuel  and  of  labor  ? 


2  Ventilation. 

Now  when  the  best  results  from  the  forge  demand  a  con- 
tinuous action  of  the  bellows,  feeding  in  more  than  11 
pounds  of  pure  air  through  the  fire  for  each  pound  of  coal 
burned,  and  when  the  health  and  best  action  of  the  smith 
demand  more  than  20  cubic  feet  of  pure  air  per  hour,  what 
would  you  think  of  setting  up  and  operating,  in  an  8  by  8 
room  without  chimney  and  with  doors  and  windows  closed, 
such  a  combination  of  forge  and  man  during  ten  consecu- 
tive hours,  depending  for  the  renewal  of  air  upon  such 
leakage  as  may  take  place  through  walls  and  ceiling?  And 
yet  are  not  conditions  more  deplorable  than  these  found  in 
many  a  sleeping  chamber,  stable,  bee-hive,  factory  and 
church?  Do  we  not  realize  and  generally  practice  in  ac- 
cordance with  the  fact  that  closing  the  drafts  in  a  stove 
checks  the  intensity  of  the  fire  or  extinguishes  it  altogether  ? 
Do  we  not  understand  perfectly  that  the  proper  action  of  a 
stove  or  of  a  furnace  can  only  be  secured  through  the  ef- 
fective action  of  a  good  chimney?  Do  we  not  know  most 
thoroughly  that  we  may  go  for  days  without  food,  and  even 
without  water,  but  that  to  be  deprived  of  air  for  only  a  few 
minutes  results  in  the  greatest  distress  and  may  even  prove 
fatal?  Have  we  not  felt  the  oppression  which  follows  the 
closing  of  ventilators  and  windows  of  a  crowded  coach  for 
only  a  minute  or  two  to  shut  out  the  smoke  while  the  train 
passes  through  a  tunnel,  and  do  we  not  recall  how  everyone 
is  looking  anxiously  for  the  windows  and  ventilators  to  be 
opened  the  moment  the  train  emerges  ? 

How  can  it  be,  then,  that  today,  even  in  cities  where 
homes  are  planned  by  trained  architects,  little  or  no  thought 
is  given  to  making  special  provision  for  ventilation  in  the 
majority  of  dwellings.  First  of  all,  must  not  the  house  be 
cheap,  then  if  it  can  be  warm,  light,  convenient,  commod- 
ious and  attractive  are  not  these  clear  gains?  If  we  can 
cook,  wash  and  iron  with  gasolene,  a  blue-flame  oil  stove, 
gas  or  electricity,  then  may  not  the  expense  of  one  chim- 
ney be  saved?  And  if  we  will  heat  the  house  with  hot 
water  or  with  steam  may  not  every  room  then  be  as  nearly 
an  air  tight  box  as  the  materials  and  the  mode  of  construe- 


Ventilation  of  Body  Tissues.  3 

tion  makes  possible  ?  And  with  such  arrangements  may  not 
the  work  and  the  warming  of  the  house  be  done  with  the 
least  possible  expense  for  fuel?  Most  certainly,  but  how 
about  the  health  and  comfort  of  the  family  for  whom  the 
home  was  built?  Which  is  better,  a  close  house  with  but 
little  air,  to  be  breathed  and  burned  over  and  over  again, 
with  langour  and  irritableness,  and  perhaps  less  of  service 
through  sickness  and  a  large  doctor's  bill,  or  an  airy  home, 
full  of  buoyancy,  cheer  and  health  but  perhaps  a  trifle 
larger  bill  for  coal? 

Is  it  urged  that  the  wind  will  force  air  enough  through 
the  house  and  stable  even  with  the  closest  possible  construc- 
tion? But  how  about  the  days  and  the  nights  when  there  is 
little  or  no  wind  ?  Then  the  windows  may  be  opened  ?  But 
who  thinks  to  do  this  at  the  right  time?  Perhaps  the  one 
in  the  family  who  suffers  most  from  insufficient  change  of 
air  is  too  unselfish  or  too  sensitive  lest  some  one  else  would 
be  disturbed  by  opening  the  windows,  or  perhaps  the  herds- 
man has  too  little  thought  for  the  animals  in  the  stable  to 
take  the  necessary  trouble  at  the  proper  time.  Clearly,  if 
an  abundant  change  of  air  is  needful,  a  flow  should  be  con- 
tinuous and  sufficient  at  all  times,  whether  we  are  awake 
or  asleep,  and  whether  attention  is  given  to  it  or  not.  That 
an  abundant  change  of  air  in  the  house  or  in  the  stable  is 
needful  there  can  be  no  doubt,  and  that  this  cannot  take 
place  unless  proper  arrangements  are  provided  for  it  is 
likewise  evident. 


NATURE'S  PROVISION  FOR   VENTILATION  OF   BODY-TISSUES. 

So  great,  so  imperative  and  so  constant  is  the  need  of 
fresh  air  in  the  maintenance  of  vigorous  bodily  functions 
that  the  delicate  lining  membrane  of  the  lungs  of  an  ordi- 
nary man,  in  contact  with  which  air  is  brought  and  through 
which  all  the  blood  of  the  body  circulates,  were  it  spread 
out  in  a  continuous  sheet,  would  measure  no  less  than  236 
square  feet,  enough  to  cover  the  sides,  floor  and  ceiling  of 


4  Ventilation. 

a  room  more  than  6  by  6  by  6  feet,  and  that  of  a  1000-pound 
cow  would  similarly  cover  a  room  11  by  11  by  11  feet. 


Fig.  2.— The  area  of  this  room,  walls,  floor  and  ceiling,  6  by  6  by  6  feet, 
represents  the  amount  of  surface  in  the  lungs  of  an  ordinary  man 
through  which  all  the  blood  of  the  body  passes  about  twice  every 
minute,  to  be  brought  close  to  the  air  which  is  changed  by  the  act  of 
breathing  15  to  20  times  per  minute. 

Such  enormous  surfaces  as  236  square  feet  of  delicate 
lining  membrane,  in  the  lungs  of  man,  and  of  1,500  square 
feet  in  those  of  the  cow,  may  seem  impossible.  That  this  is 
not  so  may  be  understood  when  it  is  said  that  a  box  one  foot 
on  each  side  has  an  inside  surface  of  six  square  feet.  Pass 
a  partition  through  the  center  of  this  box  each  of  the  three 
ways.  The  eight  chambers  so  formed  have  double  the  ag- 
gregate inside  surface  of  the  original  box,  or  twelve  square 
feet  per  cubic  foot  of  space.  By  passing  ten  planes  through 
the  box  in  each  of  the  three  ways  we  would  increase  the  in- 
side surface  ten-fold,  giving  it  60  square  feet,  and  so  40 
such  partitions  passing  in  each  of  the  three  directions  would 
increase  the  inside  area  40-fold,  giving  just  about  the  lung 
surface  for  man,  and  yet  each  of  the  64,000  small  chambers 
so  formed,  three-tenths  of  an  inch  on  a  side,  would  be  very 
much  larger  than  the  actual  air-cells  in  the  lungs.  In  the 


Extent  of  Lung  Surface.  5 

box  represented  in  Fig.  3,  subdivided  by  40  planes  passing 
each  way,  the  small  divisions  are  each  one-twelfth  of  an 
inch  in  diameter,  easily  visible,  and  the  total  wall  surface 
formed  by  them  measures  no  less  than  18.5  square  feet  and 
about  one-twelfth  the  lung  surface  of  man,  thus  making  it 
clear  how  a  very  large  surface  may  be  developed  in  a  small 
space. 


Pig.  3.— A  box  the  size  of  this  drawing,  subdivided  by  as  many  parti- 
tions as  are  represented  by  the  lines,  would  form  64,000  chambers 
having  a  total  wall  surface  of  18.5  square  feet,  one-twelfth  that  In  the 
lungs  of  an  ordinary  man. 

Now  imagine  blood  flowing  steadily  through  a  close  net- 
work of  capillaries  within  all  the  partitions  in  this  box, 
and  at  the  same  time,  by  a  bellows-like  action,  that  the  air 
is  drawn  into  and  forced  out  of  it  15  to  20  times  every- 


6  Ventilation. 

minute,  and  you  have,  then,  a  fairly  truthful  illustration  of 
the  principle  underlying  the  mechanism  by  which  the  blood 
of  the  body  is  brought  continuously  into  close  touch  with  a 
fresh  supply  of  air.  The  blood  vessels,  bringing  all  of  the 
blood  of  the  body  to  the  lungs,  subdivide  and  spread  out 
until  they  expose  to  the  air  in  the  air-cells  some  236  square 
feet  of  blood  surface,  flowing  in  the  thinnest  possible 
streams  almost  in  touch  with  air  on  two  sides,  which  is 
being  renovated  by  15  to  20  respirations  every  minute, 
while  the  powerful  action  of  the  heart  drives  the  whole 
blood  of  the  body  over  this  large  surface  once  every  20  to 
40  seconds. 

There  is  another  remarkable  feature  in  the  wonderful 
mechanism  which  nature  has  found  necessary  to  make  sure 
that  oxygen  shall  be  brought  to  and  carbon  dioxide  re- 
moved from  the  body  tissues  as  rapidly  as  is  needful.  The 
water  of  the  blood,  although  comprising  80  per  cent  of  its 
weight,  does  not  have  a  sufficiently  strong  absorbing  power 
to  permit  it  to  take  up  oxygen  in  the  lungs, .  exchanging  it 
for  carbon  dioxide  in  the  tissues,  as  rapidly  as  is  needful 
"and  hence  more  than  half  the  volume  of  the  blood  is  put 
into  the  form  of  circular,  cracker-shaped  disks  called  the 
red  corpuscles,  giving  its  characteristic  color.  These  cor- 
puscles strongly  absorb  oxygen  when  in  the  lungs  and  ex- 
change it  for  carbon  dioxide  when  in  the  tissues,  thus  act- 
ing like  so  many  conveying  buckets  which  are  continuously 
loading  and  unloading  with  each  round  trip  and  yet  with- 
out stopping.  Moreover,  to  make  sure  that  each  one  of  these 
carriers  shall  be  brought  in  touch  with  air  before  it  can  re- 
turn to  the  body,  the  diameters  of  the  capillaries  are  made 
so  small  that  these  absorbing  disks  are  compelled  to  pass 
through  them  almost  in  single  file  with  both  faces  almost 
continuously  in  touch  with  the  lining  membrane  of  adjacent 
air  cells,  thus  insuring  ample  opportunity  for  the  unloading 
of  the  carbon  dioxide  brought  from  the  tissues,  and  for  the 
reloading  with  oxygen  to  be  carried  back. 

There  is  represented  on  the  right  in  Fig.  4  a  face  view 
with  a  cross-section  of  one  of  these  oxygen  and  carbon  diox- 


Carriers  of  Oxygen-food.  7 

ide  carriers  magnified  some  2,650  diameters,  and  on  the  left 
a  single  capillary  with  the  corpuscles  passing  through  it  in 
single  file. 


Fig.  4.— Here  is  seen,  on  the  right,  the  shape  of  the  oxygen  and  carbon 
dioxide  carriers  in  the  blood  of  man,  magnified  2,650  diameters  and, 
on  the  left,  a  line  of  them  passing  single  file  through  a  capillary, 
magnified  about  600  diameters. 


These  carriers  of  oxygen-food  to  the  body  tissues  and  of 
carbon-dioxide-waste  from  them,  although  so  extremely 
minute,  are  yet  so  numerous  that  the  total  surface  of  the 
corpuscles  in  the  blood  of  an  ordinary  vigorous  healthy 
man  measures  no  less  than  49,000  square  feet,  or  more  than 
a  full  acre.  Think  of  the  heart,  with  its  70-odd  strokes  per 
minute,  sending  more  than  a  full  acre  of  bucket  faces 
through  the  236  square  feet  of  partition  surface  in  the 
ventilation  chamber  of  the  body  once  every  20  to  40  sec- 
onds, and  the  air  of  this  chamber  changed  15  to  20  times 
every  minute !  Nor  is  this  the  whole  story  of  the  structural 
arrangements  in  the  mechanism  of  breathing  by  which  the 
body  tissues  shall  be  fed  oxygen  and  freed  from  carbon-di- 
oxide-waste, for  it  is  at  once  clear  that  the  flattened  shape 
of  the  blood  disks  gives  to  them  not  only  the  largest  ab- 
sorbing surface  but  at  the  same  time  it  provides  the  short- 
est possible  distance  over  which  these  gases  must  travel  to- 
enter  and  leave  the  tissues,  which  must  take  place  by  the 
only  available  but  peculiarly  slow  process  of  diffusion. 

Everything,  therefore,  points  to  the  most  imperative  need 
of  a  thorough  ventilation  of  the  body  tissues.  But  when  we 
are  brought  to  realize  how  superlatively  efficient  this  mech- 


8  Ventilation. 

anism  for  breathing  is  we  can  never  afford  to  forget  that  it 
grew  into  its  marvelous  efficiency  unhampered  by  any  of 
the  restrictions  or  constrictions  imposed  by  fashion,  and 
when  all  of  the  breathing  was  done  in  the  pure  free  air  of 
field  and  forest.  Nature  has  provided  a  very  large  margin 
of  safety  in  this,  as  in  other  matters  meaning  life  or  death 
to  organisms  which  are  the  present  survivors  of  uncounted 
generations  which  have  come  and  gone.  For  such  as  are 
content  to  bestow  their  affections  upon  pug  dogs  while  they 
give  their  lives  to  the  amusement  of  a  brotherhood  enter- 
taining if  possible  less  lofty  aims  in  life  perhaps  the  world 
need  not  be  concerned ;  but  for  those  who  project  their  lives 
into  the  future  may  God  and  all  the  forces  which  conspire 
to  better  living  do  everything  possible  to  make  deep  breath- 
ing easier  and  more  certain  and  to  maintain  a  standard  of 
purity  of  air  in  the  home  and  in  the  stable  which  ap- 
proaches closely  that  in  the  open  field.  It  is  along  such 
lines  of  the  fullest  utilization  of  our  natural  resources,  even 
more  than  to  the  husbanding  of  them,  that  we  need  to  look 
if  a  race  shall  be  perpetuated  capable  of  highest  civilization 
and  which  will  be  lead  on  by  higher  ideals.  How  can  we 
liope  to  combat  disease,  maintain  and  transmit  bodily  vigor, 
when  the  very  breath  of  life  is  shut  out  of  our  bodies  by 
thoughtless  false  standards  of  dress  and  from  our  homes 
and  stables  by  lack  of  sufficient  thought  given  to  proper 
construction? 

1      AMOUNT  OP  AIR  REQUIRED  FOR  A  DAILY  RATION. 

The  complete  consumption  of  a  pound  of  hay  or  of  grain, 
in  the  body  of  an  animal,  converting  it  into  carbon  dioxide 
and  water,  would  require  the  same  amount  of  oxygen  as 
though  it  were  burned  in  a  stove  or  on  the  grate  of  an  en- 
gine boiler.  Speaking  in  approximate  round  numbers  the 
burning  of  a  pound  of  hard  coal  requires  all  of  the  oxygen 
carried  in  some  11  pounds,  or  136  cubic  feet,  of  air  and  the 
burning  of  one  pound  of  hay  requires  all  the  oxygen  in 
some  5  pounds  or  62  cubic  feet.  But  when  rapid  and  com- 


Amount  of  Air  Required  Daily. 


9 


plete  combustion  takes  place  not  all  of  the  oxygen  in  the 
air  can  be  consumed  and  hence  much  more  than  136  cubic 
feet  of  air  per  pound  of  coal,  and  than  62  cubic  feet  per 
pound  of  hay,  must  pass  through  the  fire  box  for  each 
pound  of  material  consumed.  Moreover  it  is  important  to 
keep  in  mind  that  air  is  as  much  a  part  of  the  fuel  which 
produces  the  fire  as  is  the  coal  or  the  wood,  indeed,  even 
more  so  when  considered  pound  for  pound.  And  so  is  the 
air  an  animal  breathes  as  much  an  indispensable  part  of  the 
food  it  consumes  as  is  the  hay  or  the  grain  eaten.  In  the 
furnace  neither  can  burn  without  the  other  and  so,  within 
the  animal  body,  neither  assimilation  of  food  nor  genera- 
tion of  energy  can  take  place  without  the  consumption  of  a 
proportionate  amount  of  air.  When  an  engine  is  being 
crowded  to  its  full  capacity  in  the  generation  of  power  not 
only  must  the  stoking  be  more  rapid  but  the  drafts  also 
must  be  opened  wider  that  more  air  may  pass  through  the 
fire ;  and  so  it  is  with  an  animal  when  doing  work,  no  mat- 
ter of  what  kind,  it  must  breath  more  deeply  or  more  fre- 
quently. We  realize  this  clearly  in  our  own  case  and  we 
see  it  in  the  horse,  the  ox  or  the  dog,  when  they  are  in  vio- 
lent exercise.  Even  in  the  case  of  the  heavy  feeding  of 
animals  for  the  production  of  milk  or  of  flesh  proportion- 
ately more  air  must  be  breathed,  and  hence  when  animals 
are  closely  housed  under  these  conditions  more  air  should 
pass  through  the  stable  each  day. 

The  amount  of  pure  air  which  must  be  breathed  by  differ- 
ent animals  during  24  hours,  in  order  to  supply  the  oxygen 
needed,  computed  from  Colin 's  table,  is  given  below: 

Amount  of  air  breathed  by  different  animals. 


Per  hour. 

Per  24  hours. 

cu.  ft. 

Ibs. 

cu.  ft. 

Volume. 

Horse 

141.7 
116.8 
46.0 
30.2 
17.7 
1.2 

272 
224 
89 
58 
34 
2 

3401 
2804 
1103 
726 
425 
29 

15  x  15  x  15  ft. 
14  x  14  x  14  ft. 
10  x  10  x  10  ft. 
9x   9x   9ft. 
8x    8x    8ft. 
3x   3x   3ft. 

Cow  .  .  . 

Pig 

Sheep  

Man  .  . 

Hen  

10 


Ventilation. 


From  this  table  it  appears  that  a  horse  must  draw  into 
and  force  out  of  his  lungs,  on  the  average,  each  hour,  some 
142  cubic  feet  of  air,  the  cow  117,  the  pig  46,  the  sheep  30 
and  the  man  18  cubic  feet.  These  volumes  are  represented 
in  Fig.  5. 


Fig.  5.— Here  each  small  square  In  the  Illustration  represents  one  foot 
and  each  pile  of  cubes  the  volume  of  air  breathed  each  hour,  which 
should  be  nearly  pure. 

If  it  were  necessary  to  supply  air  to  our  stock  as  we  do 
water  the  horse  would  require  continuously  7  full  pails  per 
minute ;  the  cow,  6 ;  the  pig,  2 . 3,  and  the  sheep,  1 . 5  full 
pails  of  air,  and  these  are  the  amounts  required  when  it  is 
supplied  pure  and  fresh  with  each  respiration,  as  would  oc- 
cur out  of  doors  where  there  is  a  free  air  movement  and 
where  the  air  thrown  off  from  the  lungs  is  at  once  borne 
away  by  the  winds;  Inside  a  dwelling  or  stable  the  condi- 
tions would  be  very  different  unless  some  means  were  pro- 
vided to  maintain  a  constant  change  of  air  at  the  proper 
rate. 


Air  Breathed  Loses  in  Sustaining  Power. 


11 


AIR  ONCE  BREATHED  HAS  LOST  MUCH  OF  ITS  SUSTAINING 
POWER. 

Air  once  breathed  has  lost  much  of  its  food  value  or  sus- 
taining power  and,  impossible  as  it  may  seem,  we  have 
known  horses  to  suffer  from  breathing  impoverished  air 
when  plowing  in  the  open  field.  This  may  occur  where 
three  horses  driven  abreast  have  their  heads  close  and  so 
directed  that  the  middle  animal  is  compelled  to  draw  his 
supply  of  air  from  that  thrown  out  by  the  other  two,  and 
the  exhaustion  or  fatigue  of  the  center  horse  can  often  "be 
made  noticeably  less  when  a ' '  spreader ' '  or  the  habit  of  driv- 
ing requires  the  outside  animals  to  breathe  straight  in  front 
or  a  little  outward.  Three  heavy  horses  at  hard  labor  on 
the  plow  or  harvester  draw  so  much  air  and  reduce  its  feed- 
ing value  to  suoh  an  extent  that  when  the  outer  horses  are 
permitted  to  travel  a  little  in  advance  and  at  the  same  time 
incline  their  heads  in,  the  center  animal  is  placed  at  a  great 
disadvantage  in  being  compelled  to  breathe  partly  ex- 
hausted and  otherwise  viti- 
ated air,  for  the  case  is  like 
feeding  the  firebox  of  one  en- 
gine from  the  smokestacks  of 
two  others.  So,  too,  when  a 
large  number  of  sheep  are 
driven  long  distances  in  a 
closely  huddled  flock  much 
discomfort  results  from  their 
being  compelled  to  breathe 
exhausted  air. 

Everyone  has  observed  that 
of  two  glowing  coals  in  the 
open  air  the  one  which  has  a 
strong  current  forced  across 
it  burns  more  rapidly  and  with  a  more  intense  glow.  Why 
is  this?  Clearly  because  one  has  a  more  rapid  change  of 
air,  is  better  ventilated,  even  though  both  may  be  out  of 
doors.  Immediately  about  the  burning  coal  the  oxygen  of 


Fig.  6. — The  air   blown   across 
one  coal  increases  the  glow. 


12 


Ventilation. 


the  air  is  both  partly  exhausted  and  diluted,  and  the  cur- 
rent drives  the  used  air  away,  bringing  fresh  air  instead. 
And  so  ventilation,  even  out  of  doors,  may  be  helpful.  The 
lamp  without  a  chimney  gives  little  light  and  smokes  badly 
but  the  flame  surrounded  with  a  chimney,  which  seemingly 
shuts  off  the  free  access  of  air,  burns  much  better  and 
simply  because  it  gets  a  more  rapid  change  of  air.  The 
chimney  compels  a  stream  to  flow  rapidly  close  to  the  flame 
and  thus  is  swept  away  the  used  air  while  a  fresh  supply 
takes  its  place.  And  so,  the  lamp,  the  stove,  the  engine  and 
the  forge,  whether  in  an  enclosure  or  out  of  doors,  must 
have  a  mechanism  securing  a  continuous  forced  change  of 
air ;  and  the  respiratory  movements  of  every  air-breathing 
animal  tell  of  the  same  imperative  need.  And  yet,  dwell- 
ings and  stables  are  planned,  adopting  increasingly  close 
construction,  allowing  ventilation  to  be  brought  about  inci- 
dentally as  it  may,  without  special  provision.  Only  last 
summer  in  conversation  with  a  New  York  City  architect  it 
appeared  that  he  had  recently  completed  a  residence  in  ce- 
ment concrete  and  was  much  surprised  to  find  that  the  fire- 
place would  invariably  smoke 
unless  a  door  or  window  of 
the  room  was  open. 

Here  is  perhaps  a  more 
striking  demonstration  of  the 
need  of  ventilation  and  of  the 
fact  that  air  once  breathed 
has  lost  in  sustaining  power. 
In  the  illustration,  Fig.  7, 
from  a  photograph,  a  coil  of 
magnesium  ribbon  is  shown 
burning  in  ordinary  air  sup- 
plied by  convection  currents 
through  the  open  mouth  of  a 
two-quart  Mason  jar.  The 
intense  light  which  fills  the 
jar  and  the  cloud  of  white  gmoke  escaping  above  show 
how  strong  is  the  burning;  while  in  Fig.  8  is  shown 


Fig.  7. — Magnesium  ribbon 
burning  in  ordinary  air. 


Composition  of  the  Atmosphere. 


13 


a  similar  piece  of  the  same  ribbon  burning  in  the  same  jar, 
but  here  supplied  with  air  from  the  lungs,  conveyed 
through  the  rubber  tube.  Very 
markedly  less  intense  is  the 
burning  and  the  light  pro- 
duced in  this  case,  and  far 
less  is  the  cloud  of  smoke. 
It  is  of  course  the  diminished 
volume  per  cent  of  oxygen 
carried  by  the  respired  air 
which  causes  the  difference  in 
the  intensity  of  burning,  for 
the  rate  of  change  of  air  is 
greater  in  this  case. 

The  composition  of  pure 
dry  air  and  of  air  carrying 
75  per  cent  of  its  saturated 
volume  of  moisture,  deduced 
from  data  of  Clarke  published 
in  1908  from  the  most  recent 
and  authoritative  determina- 
tions, are  given  in  the  next 
table  : 


Fig.  8. — M:ij*iiesium  ribbon 
burning  in  respired  ;iir. 


(  ''>//, jtox/'f/otl    of  the  Atllioxjilu  r i  . 


Volume 
pel-  cent. 

Cubic  inches 
per  cubic  foot. 

Dry  air: 
Carbon  dioxide                

0292 

506 

Oxygtsn 

°()  (U1 

361  860 

Xit  roiren  and  other  grasps  

?.<  o:;o 

1365  634 

Air.  humidity  75  per  cent: 
Carbon  dioxide              

028 

484 

Oxygen 

90  582 

355  657 

\  il  i'<  >yen  and  other  gases  

77  ti77 

1342  256 

Moistu  re 

1  7i:> 

29  603 

14 


Ventilation. 


On  the  average,  in  the  case  of  man,  it  is  found  that  once 
respired  air  has  lost  oxygen  to  the  extent  of  4.78  volume 
per  cent.  It  has  acquired  4.35  volume  per  cent  of  carbon 
dioxide  and  has  become  saturated  with  moisture  at  the  tem- 
perature of  the  respired  air,  while  its  volume  has  been  in- 
creased by  the  expansion  due  to  the  rise  in  temperature. 
Each  of  these  changes  reduces  the  absolute  amount  of  oxy- 
gen which  may  enter  the  lungs  in  a  given  time  when  the  air 
is  respired  again,  unless  the  depth  or  frequency  of  breath- 
ing is  increased. 

The  changes  in  composition  which  come  to  once  breathed 
air  are  indicated  in  the  next  table,  where  dry  air  and  that 
75  per  cent  saturated  with  moisture  before  breathing  are 
the  basis  of  computation. 

Composition  of  pure  air  and  of  that  once  breathed. 


Pure  air, 
cubic  inches 
per  cu.  ft. 

Airbreathed. 
cubic  inches 
per  cu.  ft. 

Change, 
cubic  inches 

Dry  air: 
Oxygen  ...                              ... 

361  860 

265.920 

—95.94 

Carbon  dioxide  

.506 

72.059 

+71.553 

Nitrogen  and  other  gases  

1365  634 

1300  400 

—65.234 

Moisture  

89.638 

+89.638 

Air.  humidity  75  per  cent: 
Oxygen  

355.657 

264.330 

—91.327 

Carbon  dioxide 

484 

73  232 

+72.748 

Nitrogen  and  other  gases  
Moisture  

1342.256 
29  630 

1300.800 
89.638- 

—41.456 
+60.008 

Here  it  is  seen  that  air  once  breathed  may  contain,  per 
cubic  foot,  from  91  to  96  cubic  inches  less  oxygen,  more 
than  70  cubic  inches  increase  in  carbon  dioxide  and,  if  the 
air  is  dry,  some  90  cubic  inches  more  of  moisture.  The  oxy- 
gen has  been  decreased  from  a  volume  per  cent  of  20.94  to 
one  of  about  15.39,  thus  leaving  it  only  three-fourths  as 
rich  in  its  essential  food  element.  This  reduction  of  the 
oxygen  content  of  the  air,  first  by  the  direct  consumption 
of  it  and,  second,  by  its  dilution  through  the  addition  of 
other  ingredients  and  by  expansion  due  to  rise  in  temper- 
ature, must  be  the  main  change  which  reduces  its  sustain- 
ing power.  Indeed  breathing  becomes  difficult  so  soon  as 


Composition  of  Once  Breathed  Air. 


15 


the  volume  per  cent  of  oxygen  in  the  air  has  fallen  as  low 
as  13,  so  that  breathing  the  air  but  twice  would  carry  the 
volume  per  cent  of  oxygen  below  ^^^^^^^^^^ 
this  limit,  indeed  as  low  as  10  per 
cent  if  no  fresh  air  were  added 
to  it. 

We  have  seen  with  what  dimin- 
ished brilliancy  a  magnesium  rib- 
bon burns  in  air  once  breathed. 
Here  is  perhaps  a  more  convincing 
concrete  demonstration  of  the  loss 
of  power  to  support  combustion 
and  to  sustain  bodily  functions 
which  cliMnicnti-rizes  respired  air. 


Fig.   10.— Candle  extinguished 
in  air  once  brc.-ithrd. 

Using  again  the  two-quart  Mason 
jar,  Fig.  9,  let  a  lighted  candle  be 
lowered  into  it.  It  burns  with 
scarcely  diminished  intensity,  as 
did  the  ribbon,  for .  down-going 
and  up-going  currents  maintain  a 
continuous  fresh  air  supply.  Now 
while  the  candle  is  yet  burning  let 
a  gentle  stream  of  air  from  the 
lungs  be  conveyed  to  the'  bottom 
of  the  jar,  Fig.  10.  Gradually,  as 
the  jar  fills,  the  flame  loses  in 
brilliancy  and  finally  is  extin- 
guished. The  flame  in  this  case  is  certainly  not  blown  out 
by  the  air  current  for  the  candle  may  be  relighted  and  again 


Fig.  9. — Candle  burning  in 
pure  air. 


16 


Ventilation. 


lowered  into  the  jar  after  removing  the  tube.  The  respired 
air  is  heavy  enough  to  remain  and,  as  the  candle  is  lowered 
into  it,  it  will  be  extinguished, 
even  after  the  lapse'  of  more  than 
two  minutes  if  the  air  in  the  room 
is  still. 

Once  more  let  the  candle  be 
lighted  and  lowered  into  the  jar, 
Fig.  11.  Gradually  raise  the'  can- 
dle as  the  flame  shows  signs  of  go- 
ing out.  Observe  that  the  respired 
air  tends  to  remain  at  the  bottom, 
as  may  be  proven  by  repeatedly 
lowering  the'  candle,  observing  that 
as  this  is  done  the  flame  tends  to 


Fig.  11.— The  respired  air 
tends  to  remain  at  the 
bottom. 

become  extinguished.  As  the  air 
is  forced  continually  into  the  jar 
it  becomes  gradually  filled  and  the 
lighted  candle  has  taken  the  posi- 
tion represented  in  Fig.  12.  But 
even  here,  if  breathing  into  the 
jar  is  continued,  the  flame  will  be 
extinguished  as  the1  out-coming  re- 
spired air  surrounds  the  candle 
and  shuts  off  a  fresh  supply  from 
the  flame.  Clearly,  then,  air  once  Fis-  12.— The  flame  is  extin- 

,          .mm..  guished    even     when     held 

breathed  is  not  suitable  for  respir-      above  the  mouth  of  the  jar. 
ation  unless  much  diluted  with  pure  air. 


Continuous  Flow  of  Air  is  Necessary. 


17 


A  CONTINUOUS  FLOW  OF  AIR  IS  NECESSARY. 

Since  once-breathed  air  is  not  suitable  for  respiration 
until  much  diluted  with  that  which  is  pure  it  follows  that 
into  and  out  of  dwellings,  schools,  churches  and  stables,  so 
long  as  they  are  occupied,  must  be  maintained  a  sufficient 
and  continuous  flow  of  air  to  bear  away  that  whose  food 
value  has  been  reduced  and  to  restore  an  equal  volume  of 
that  which  is  pure.  Let  us  again  use  the  two-quart  Mason 
jar,  Fig.  9,  for  another  demon-  g_jj^g^^_ 
stration.  With  the  candle  resting 
on  the  bottom  and  the  mouth  of 
the  jar  unobstructed  the  flame 
burns  with  a  steady  uniform  bril- 
liancy. By  holding  the  hand  above 
its  mouth  a  strong  ascending  cur- 
rent may  be  distinctly  felt,  but 
such  a  continuous  up-going  cur- 
rent of  air  from  out  the  jar  can 
only  be  possible  when  an  equal 
countercurrent  is  maintained  and 
it  is  this  which  sustains  the  flow. 

Now,  with  the  candle  still  burn- 
ing in  the  jar  let  these  in-going 
and  out-going  currents  be  com- 
pletely stopped  by  screwing  in 
place  the  cover  of  the  jar,  Fig.  13. 
With  watch  in  hand  it  will  be 
found  that  in  even  less  than  30 

Seconds    the    flame    is    extinguished,     quarts    of   airaextfnguishes 

Thus  it  is  demonstrated  that  an  Itself  in  *>  S€Conds- 
ordinary  candle  spoils  for  its  own  use  a  full  gallon  of 
air  per  minute ;  60  gallons  per  hour ;  and  more  than 
200  cubic  feet  per  day.  Twenty-four  such  candles  would 
vitiate  the  air  of  a  room  for  themselves  and  for  you  at  the 
rate  of  200  cubic  feet  per  hour.  The  small  portable  kero- 
sene oil  stove  so  frequently  used  to  warm  rooms  demands 


18  Ventilation. 

more  air  than  twenty-four  candles  and  hence  the  rate  of 
change  in  the  room  for  such  conditions  must  much  exceed 
an  hourly  flow  of  200  cubic  feet,  which  is  more  than  33 
cubic  feet  per  minute.  As  the  candle  in  the  Mason  jar  ex- 
tinguished itself  in  30  seconds  where  the  walls  were  abso- 
lutely air-tight  it  is  clear  that  in  every  room  and  in  every 
stable  there  must  be  either  unintentional  leaks  for  air  to 
enter  and  escape  or  else  definitely  provided  openings ;  other- 
wise neither  lights  nor  life  could  be  long  maintained. 

Fortunately  for  mankind  and  for  his  domestic  animals  it 
has  not  been  practicable  to  build  either  dwellings  or  stables 
even  approximately  approaching  the  degree  of  impenetra- 
bility for  air  possessed  by  the  Mason  jar.  But  both  poorly 
lighted  basement  dwellings  and  stables  and  the  old  prison 
walls  and  dungeon  cells  have  come  dangerously  near  this 
limit.  Air  has  entered  and  left  dwellings  and  stables 
through  openings  formed  by  loosely  fitting  doors  and  win- 
dows, and  in  varying  degrees  under  the  pressure  of  the 
wind  through  the  walls  themselves.  Then  too,  the  oldtime 
fireplace,  the  kitchen  range  and  the  heating  stove  have 
served  a  sanitary  mission  of  the  greatest  importance  in  that 
they  have  always  compelled  a  more  or  less  continuous  in- 
flow to  dwellings  of  so  much  fresh  air  as  equalled  the  out- 
go through  the  chimney.  But  the  fireplace,  for  continuous 
service,  has  long  since  passed.  Heating  stoves  are  being  re- 
placed by  hot  water  and  steam  radiators  and  the  air  which 
warms  these  misses  entirely  the  life-giving  functions  for  it 
enters  only  the  basement  rooms,  leaving  by  the  furnace  flue, 
no  part  of  it  having  served  the  purpose  of  ventilation. 
Even  the  kitchen  stove  is  being  displaced  by  the  oil,  gas  or 
gasolene  range,  deadly  from  the  standpoint  of  pure  air,  for 
they  tend  simply  to  revolve  large  volumes  of  the  air  of  the 
room  over  and  over,  consuming  its  oxygen  and  adding  to 
it  all  of  the'  products  of  combustion,  for  only  rarely  are 
they  connected  with  a  chimney. 

It  is  of  the  highest  sanitary  importance  too,  in  its  bear- 
ing upon  the  general  health  and  bodily  vigor  of  the  future, 
to  recognize  that  in  the  passing  of  lumber  as  a  building 


Definite  Provision  for  Air  Movement.  19 

material  and  in  the  substitution  therefor  of  masonry,  metal 
and  various  filled  and  painted  compositions,  both  for  out- 
side and  inside  finish  of  dwellings  and  stables,  we  are  stead- 
ily, surely  and  rapidly  approaching  the  ability  of  the  fruit 
jar  to  exclude  fresh  air,  compelling  it  to  enter  only  through 
unavoidable  leaks  about  doors  and  windows.  We  are  even 
building  flats  with  windows  and  doors  limited  to  but  one  or 
at  most  two  sides,  at  the  same  time  piling  one  over  another 
where  the  exhausted,  fouled  and  heated  air  must  rise  from 
one  to  another  through  ceilings,  floor  and  hallways.  The 
increasing  cost  of  fuel  too  is  leading  to  the  adoption  of 
storm  windows  and  doors  for  the  few  provided,  to  more  ef- 
fectually shut  out  the  wind.  It  is  difficult  to  imagine  more 
unsanitary  conditions  from  the  "fresh  air"  standpoint  than 
must  be  associated  with  a  poorly  lighted  stack  of  over- 
crowded flats  piled  one  above  another,  warmed  with  steam 
or  hot  water,  the  cooking  and  lighting  done  with  gas.  "When 
every  adult  needs  hourly,  as  food,  scarcely  less  than  18 
cubic  feet  of  the  purest  air  to  be  found  out  of  doors ;  when  we 
are  making  such  strenuous  efforts  to  shut  this  air  out  of  our 
homes  and  stables ;  when  so  little  specific  provision  is  being 
made  to  supply  air  to  them  at  an  adequate  rate ;  should  we 
not  be  surprised  rather  that  the  dread  "white  plague "  does 
not  take  even  more,  vast  as  the  number  now  is.  And  if  we 
shall  ever  be  successful  in  driving  it  from  among  us  must 
not  the  battle  be  waged  in  every  home  where  the  children 
are  yet  well  and  strong,  by  applying  continuously  and  ef- 
ficiently the  "fresh  air  treatment,"  not  leaving  it  to  be  ad- 
ministered only  at  the  hospital  'and  to  those  already 
stricken  ? 


FRESH   AIR   SUPPLY    CERTAIN   TO   BE   INADEQUATE   AT   TIMES   IF 
DEFINITE  PROVISION  FOR  IT  IS  NOT  MADE. 

Where  numbers  of  individuals  are  sheltered  in  compart- 
ments of  reasonable  volume  and  so  constructed  as  to  permit 
of  economic  warming  in  severe  weather  there  are  certain 
to  be  times  when  the  fresh  air  supply  will  be  inadequate 


20  Ventilation. 

unless  definite  provision  for  such  supply  is  made.  Let  us 
again  have  recourse  to  positive  concrete  demonstration. 
Here  is  a  cylindrical  metal  chamber,  Fig.  14,  18  inches  in 
diameter  and  20  inches  deep  having  a  cover  which  seals  the 
chamber  air-tight  by  means  of  its  rim  dipping  under  sweet 
oil  carried  in  a  groove  formed  about  the  top.  Around  the 


Fig.   14.— A  ventilation  chamber  for  observing  the  effects  of  inadequate 
change  of  air. 

sides  are  arranged  a  series  of  six  openings  each  .71  inch 
in  diameter,  which  may  be  closed  by  means  of  screw-caps ; 
and  two  air-tight  observation  windows  of  glass.  In  the 
cover  is  a  ventilation  opening  over  which  may  be  screwed 
a  short  ventilating  shaft  beginning  at  the  cover,  or  an- 
other long  enough  to  withdraw  air  from  near  the  bottom. 
Inside  the  chamber  is  placed  a  lighted  kerosene  lamp  with 
a  No.  1  burner  carrying  a  five-eighths  inch  wick,  and  turned 
up  until,  in  an  abundant  supply  of  air,  it  burns  kerqsene 
at  the  rate  of  13.783  grams  per  hour  or  .109  gallons  per 
day.  With  this  apparatus  the  following  results  were  ob- 
tained : 

(1)  With  this  ventilation  chamber  in  the  still  air  of  a 
room,  with  the  cover  on  but  not  sealed  with  oil;  with  the 
ventilator  closed  and  with  the  six  windows  open,  each  pro- 


Experimental  Ventilation  Chamber.  21 

vided  with  a  thin  muslin  screen  possessing  a  pore  space 
through  which  air  may  pass  equal  to  29 . 36  per  cent  of  the 
total  area,  it  was  found  that  in  two  minutes  the  flame 
dropped  from  full  height  to  below  the  top  of  the  shield  of 
the  burner,  and  went  out  at  the  end  of  11.5  minutes. 
Here  we  have  the  conditions  of  a  steam  or  hot  water-heated 
room  provided  with  six  open  but  screened  windows,  in 
which  the  lamp  could  burn  but  11.5  minutes. 

(2)  With  the  six  windows  open  but  screened;   with  the 
ventilating  shaft  in  place,  open  and  drawing  air  from  the 
floor  level,  the  flame  dropped  below  the  top  of  the  shield 
in  6  minutes  and  was  extinguished  in  23.5  minutes.    Here 
we  have  ample  opportunity  for  air  to  escape  from  the  room 
but  inadequate  entrance  capacity. 

(3)  With  the  six  windows  open  but  screened;   with  the 
ventilating  shaft  in  place  but  drawing  air  from  the  ceiling, 
the  flame  fell  below  the  top  of  the  shield  at  the  end  of  9 
and  was  extinguished  at  the  end  of  27  minutes.     In  this 
case,  with  the  hottest  air  at  the  ceiling  and  able  to  enter  the 
ventilating  shaft  at  that  level,  a  stronger  draft  was  pro- 
duced, compelling  a  larger  supply  to  enter  through  the 
window  screens. 

(4)  With  all  of  the  conditions  the  same  as  in  (3)  except 
that  the  muslin  was  removed  from  one  window,  in  16  min- 
utes the  flame  fell  below  the  top  of  the  shield  but  at  the- 
end  of  two  hours  was  still  burning,  showing  no  signs  of 
going  out.    In  this  case  the  hottest  air  is  able  to  fill  the  ven- 
tilator and  with  the  same  difference  of  pressure  but  with 
one  window  entirely  free  more  air  may  be  drawn  in  in  a 
unit  of  time,  the  amount  being  barely  sufficient  to  maintain 
a  small  flame. 

(5)  When  an  8-inch  electric  fan  was  so  placed  as  to- 
throw  a  strong  current  of  air  directly  across  the  top  of  the 
ventilator,  but  with  no  direct  current  against  the  windows, 
the  small  flame  being  maintained  under  the  conditions  of 
(4)  was  in  one  minute  increased  in  size  to  its  normal  free 
air  dimensions.    Here  we  have  five  windows  screened,  one 
window  open,  and  a  strong  wind  blowing  across  the  top  of 


22 


Ventilation. 


the  ventilator,  the  wind  increasing  the  draft  until  the  cham- 
ber is  sufficiently  ventilated  to  meet  the  needs  of  the  lamp. 

(6)  With  the  fan  still  run- 
ning and  unchanged  in  posi- 
tion with  but  the  ventilator 
closed  the  flame  in  6  minutes 
fell  below  the  shield  on  the 
burner  and  at  the  end  of  16 
n  mutes  had  extinguished  it- 
self. "With  the  strong  wind 
blowing  over  the  top  of  the 
chamber,  with  the  six  win- 
dows open  and  five  of  them 
screened,  but  without  an  ac- 
tive ventilating  shaft,  an  in- 
adequate supply  of  air  was 
provided. 

In  Fig.   16   are  shown  the 
relative     dimensions     of    the 
flame    under    the   five   condi- 
tions   stated    by    the    corre- 
sponding legend. 
In  these  trials  the  wind  blew  directly  against  the  windows 
and  sides  of  the  chamber  and  the  air  movement  was  meas- 
ured with  a  delicate  air  meter. 

In  another  demonstration  a  silver-laced  Wyandotte  roos- 
ter weighing  5 . 5  pounds  was  substituted  for  the  lamp  in  the 
chamber  of  Fig.  14.  The  ventilator  and  five  windows  were 
closed,  the  other  screened  with  muslin.  Under  these  con- 
ditions and  surrounded  by  an  air  temperature  of  60°  F.  at 
the  end  of  5.5  hours  the  bird  was  in  distress,  breathing 
heavily,  gasping  with  each  inspiration.  At  this  stage  the 
six  windows  were  all  opened  but  covered  with  the  screens 
and  2.5  hours  later  the  bird  was  still  breathing  even  more 
^heavily  and  with  greater  distress.  The  ventilator  in  the 
cover  was  then  opened  but  covered  with  a  screen.  After 
10  hours  there  had  been  perhaps  a  little  improvement,  if  so 
it  was  very  slight.  The  screens  were  then  all  removed  from 


Pig.  15. — Wind  across  ventilator 
Increases  draft. 


Effects  of  Insufficient  Ventilation.  2$ 

windows  and  ventilator  and  at  the  end  of  2  hours  the  roos- 
ter was  standing  up  apparently  comfortable  and  breathing 
normally,  presumably  he  was  getting  air  sufficient  to  meet 
his  needs.  It  should  be  observed,  however,  that  in  this  case 
special  provision  is  made  for  both  incoming  and  outgoing 
currents. 

VARIATION  IN  THE  SIZE  OF  FLAMES  UNDER  PERFECT 
AND  IMPERFECT  VENTILATION 


1.  Windows    all    open;    wind    7.39    miles    per    hour; 

ventilator  at  top. 

2.  Windows  all  open;   air  still;   ventilator  at  top. 

3.  Windows  all   open;    air  still;    ventilator  closed. 

4.  Screens    on    all    windows;    wind    10.97    miles    per 

hour;    ventilator  closed. 

5.  Screens    on    all    windows;    wind    3.26    miles    per 

hour;   ventilator  closed. 

F\g.  16.— Here  are  represented  five  sizes  of  flames,  natural  size,  as 

were  maintained  tinder  the  ventilation  conditions  named  in  Nos.  1,  2, 
3,  4,  5,  the  burner  being1  that  of  the  lamp  and  the  chamber  the  same 
as  shown  in  Fig.  14. 

A  hen  of  the  same  breed  weighing  4 . 5  pounds,  placed  in 
the  same  chamber  with  all  openings  closed,  became  severely 
distressed  for  want  of  ventilation  at  the  end  of  4  hours,  13 
minutes  and  died  from  the  effects  4  minutes  later.  In  this 
case  the  cover  was  sealed  with  oil  and  corresponds  with  the 
trial  with  the  candle  in  the  two-quart  Mason  jar,  Pig.  13, 
which  extinguished  itself  in  30  seconds,  the  chamber  having 
44  times  the  capacity  of  the  two-quart  jar.  The  candle  was- 


24  Ventilation. 

breathing  in  115.5  cu.  in.  of  air  and  died  in  30  sec.,  using 
3.85  cu.  in.  per  sec. ;  the  hen  was  breathing  in  5,089  cu.  in. 
and  died  in  15,420  sec.,  using  but  .  33  cu.  in.  per  sec. 

SERIOUS  EFFECTS  FOLLOW  INSUFFICIENT  VENTILATION. 

In  the  demonstrations  made  with  the  ventilation  cham- 
ber referred  to  in  the  last  section  (Figs.  14  and  15)  it  was 
made  clear  that  as  the  ventilation  became  less  and  less  per- 
fect the  size  of  the  flame  of  the  lamp  was  reduced  until  in 
the  end  it  was  no  longer  able  to  maintain  itself.  So,  too, 
must  it  be  with  the  functional  activities  of  the  body.  The 
processes  and  conditions  which  maintained  the  flame  of  the 
lamp  are  identical  in  principle  with  those  which  maintain 
the  functional  activities  of  the  various  org'ans  of  the  body. 
The  rate  of  the  carrying  of  oxygen  to  the  flame  and  that  of 
the  bearing  away  of  the  products  of  combustion  determined 
its  size  and  the  intensity  of  the  heat  and  light  generated  by 
it,  these  decreasing  from  1  through  2,  3  and  4  to  5  as  the  air 
movement  through  the  chamber  became  less  rapid,  and  so  it 
must  be  with  those  functional  activities  within  the  animal 
body  which  constitute  the  sum  total  of  its  life;  these  must 
decrease  in  intensity  or  magnitude  of  activity  just  in  pro- 
portion as  the  life-giving  oxygen  is  borne  to,  and  the  waste 
products  are  carried  away  from  them. 

Blood  passing  through  the  active  tissues  is  fully  vitalized 
only  when  it  is  doubly  charged,  first,  with  the  oxygen  from 
the  air  breathed  and,  second,  with  the  other  nutrients  eaten 
and  drank.  Neither  can  be  efficient  except  as  the  other  is 
present,  ample  and  effective.  The  lamp,  under  the  condi- 
tions of  5  had  an  abundance  of  oil,  the  wick  was  full,  the 
temperature  right  but  the  oxygen  was  deficient.  There 
could  be  no  larger  product  in  the  form  of  flame  except  as 
the  oxygen  supply  was  made  continuously  larger.  The  con- 
ditions for  activity  in  the  body  tissues  are  no  less  rigid; 
they  are  of  the  same  type.  It  requires  more  oats  and  more 
hay  to  maintain  day  after  day  a  team  turning  two  18-inch 
furrows  than  it  does  another  turning  two  of  12,  and  pro- 


Serious  Effects  of  Insufficient  Ventilation.  25 

portionately  more  air  must  be  taken  in.  If  you  increase 
the  daily  ration  of  grain  and  hay  with  a  view  of  doubling 
the  output  of  milk  there  is  no  other  possibility  for  the  herd 
than  for  it  to  charge  its  blood  with  enough  more  oxygen  to 
make  the  extra  product.  If  the  herd  is  in  the  free  air  of  a 
pasture  it  will  do  this  easily,  automatically  and  with  cer- 
tainty, but  if  it  is  in  a  stable  and  that  stable  has  a  wholly 
inadequate  air  movement  through  it ;  if  the  quality  of  the 
air  in  it  is  to  that  of  the  pasture  as  is  the  air  in  the  ventila- 
tion chamber  (Fig.  16)  under  the  conditions  of  3,  4  or  5 
to  those  of  1,  then  the  herd  will  be  helpless  to  help  you  and 
a  menace  to  those  who  use  its  product. 

The  extremely  serious  aspect  of  inadequate  ventilation 
results  not  so  much  from  its  effects  in  diminishing  func- 
tional activities  and  in  depressing  the  vital  powers  in  their 
ability  to  do  useful  work  as  in  its  tendency  to  derange  the 
order  of  chemical  processes  in  the  body  leading  to  the  for- 
mation and  accumulation  of  products  in  the  tissues  which 
render  the  individual  whose  functions  are  so  disturbed  pe- 
culiarly liable  to  disease  and  especially  to  those  of  zymotic 
or  contagious  types,  such  as  cholera,  smallpox,  diphtheria 
and  tuberculosis.    This  world  is  marvelously  full  of  germs 
of  unnumbered  kinds  and  possibilities.     Let  a  fire  sweep 
away  any  forest,  no  matter  how  dense  or  how  many  cen- 
turies old,  with  the  first  rain  and  genial  sun  there  springs 
out  from  the  ashes,  upon  almost  every  square  inch  of  sur- 
face laid  bare,  some  plant  from  seeds,  perhaps  of  a  hun- 
dred kinds,  wafted  thither  by  the  winds,  floated  on  the 
waters,  brought  by  the  birds  or  dropped  by  former  occu- 
pants of  the  soil;   seeds  which  have  laid  dormant  perhaps 
many  years  or  which  have  been  resown  a  thousand  times, 
waiting  the  moment  when  the  forest  should  lose  its  mas- 
tery over  the  soil.     Nature  has  neither  empty  places,  idle 
moments  nor  neglected  opportunities  where  the  conditions 
for  life  exist.    Everywhere  out  of  the  weak,  out  of  the  dy- 
ing and  out  of  the  dead,  as  well  as  out  of  the  soil  and  out 
of  water,  life  is  springing.    Eternally  is  somebody  waiting 
for  everybody's  shoes,  for  all  life  is  a  competitive  struggle, 


26  Ventilation. 

continuous,  intense,  and  hence  inadequate  ventilation  or 
anything  which  interferes  with  the  normal  action  of  the 
body,  causing  weakness,  becomes  an  entering  wedge,  open- 
ing out  an  opportunity  for  the  attack  of  some  disease  pro- 
ducing germ. 

Plant  any  seed  in  a  too  cold,  over- wet,  insufficiently  ven- 
tilated soil  and  it  at  once  absorbs  water,  its  stored  food  ma- 
terials dissolve  and,  unless  the  other  conditions  favorable 
for  germination  are  present,  this  soluble  plant  food  will  be 
at  once  appropriated  by  the  many  micro-organisms  exist- 
ing in  the  soil  and  which  are  better  able  to  thrive  under  the 
conditions  surrounding  the  seed.  The  result  is  the  seed  is 
robbed  of  its  stored  food,  its  vitality  becomes  thereby  low- 
ered and  either  its  life  is  destroyed  or  it -reaches  maturity 
giving  a  reduced  yield.  Likewise  we  should  never  forget 
that  in  the  case  of  our  own  bodies  and  in  those  of  our  do- 
mestic animals  there  is  continually  a  struggle  for  mastery 
between  the  normal  living  cells  which  constitute  the  various 
organs  and  many  lower  life  forms  always  present  in  the 
system  as  the  seed  are  in  the  forest  soil,  simply  biding  their 
opportunity.  Any  condition,  therefore,  like  that  of  an  in- 
sufficient supply  of  pure  air,  insufficient  or  improper  food 
of  other  kinds,  which  must  tend  to  lower  the  vitality  or 
intensity  of  action  in  the  cells  of  any  organ  is  likely  to 
place  them  at  the  mercy  of  the  invading  germs  which,  like 
weeds  in  the  field,  are  simply  biding  their  time  to  spring 
into  overmastering  supremacy,  thus  bringing  disease  and 
perhaps  death  as  the  result. 

We  fully  appreciate  that  in  a  highly  fertile  soil,  well 
managed,  crops  are  less  liable  to  disease  and  that  they  much 
more  readily  keep  the  mastery  over  weeds  than  they  do  on 
a  poor  soil  or  on  one  in  bad  condition,  poorly  managed.  It 
it  equally  true  with  the  organs  of  the  animal  body ;  if  they 
are  abundantly  nourished,  surrounded  by  congenial  condi- 
tions, the  possibilities  for  contracting  tuberculosis,  cholera, 
smallpox  or  other  forms  of  contagious  diseases  whose  germs 
we  must  remember  are  almost  always  about  us^  no  matter 
how  careful  we  may  be,  are  very  much  reduced.  It  is  the 


Serious  Effects  of  Insufficient  Ventilation. 


27 


body  starving  for  want  of  oxygen  or  for  want  of  any  other 

essential  food  material,  or  which  is  weakened  in  any  other 

way,  which  is  most  likely  to  be  overpowered  by  one  or  an- 

other of  these  foreign  organisms,  and  a  single  germ  may 

gain  the  mastery   over  a  system  in  weakened  condition 

where  multitudes  of  them  would  be  harmless  within  a  vig- 

orous constitution,  well  nourished  and  normally  cared  for, 

And  since  the  body  out  of  which  life 

has  gone  begins  immediately  to  pass 

into  decay    it   stands   to    reason  that 

one  sick  or  weak  must  be  more  liable 

to   suffer   from   attack   than   another 

who  is  strong,  and  the  truth  of  this  is 

abundantly    borne    out    by    statistics, 

particularly  by  those  expressing  the 

rate  of  mortality  resulting  from  con- 

tagious disease  associated  with  condi- 

tions of  inadequate1  ventilation. 

As  a  concrete  illustration  of  the 
manner  in  which  insufficient  air  may  FiswjtVfLunUPsunply'  ol 
alter  the  nature  of  chemical  changes  air-  without  smoke. 
let  this  lamp,  Fig.  17,  be'  used,  which 
is  burning  with  a  full  bright  flame 
under  the  influence  of  a  strong  cur- 
rent of  air.  The  moment  this  cur- 
rent is  cut  down  by  holding  the  hand 
under  the  draft,  Fig.  18,  the  chimney 
fills  with  a  sooty  flame  and  smoke. 
There  is  not  enough  oxygen  carried 
by  the  reduced  current  to  unite  with 
both  the  hydrogen  and  the  carbon  of 
the  kerosene  and,  as  the  hydrogen 
has  a  stronger  attraction  than  the 
carbon  ^or  oxygen>  &  appropriates  so 
nearly  the  whole  that  a  portion  of  the 
carbon  is  set  free  in  the  form  of  smoke.  There  is  thus  formed 
a  waste  product  abnormal  to  the1  lamp  in  healthful  operation 
and  if  allowed  to  continue  would  ultimately  clog  the  chim- 
3 


Fig.  i8.-LamP  burning 

piyho^r  ^suiting 

in'  smoky  flame.       ' 


28  Ventilation. 

ney  through  deposits  on  the  wall,  thus  extinguishing  the 
flame  by  entirely  shutting  off  the  air  supply.  Insufficient 
ventilation  may  in  like  manner  result  in  abnormal  chem- 
ical processes  in  the  body,  giving  rise  to  products  which  if 
allowed  to  accumulate  in  the  system  become  positively  in- 
jurious. It  is  of  course  not  intended  to  convey  the  impres- 
sion that  if  respiration  is  compelled  to  go  on  in  an  insuf- 
ficient supply  of  oxygen  carbon  will  be  deposited  in 
the  tissues,  as  soot  was  deposited  on  the  chimney,  but  there 
are  good  reasons  for  thinking,  indeed  direct  observations 
show,  that  when  there  is  an  insufficient  supply  of  oxygen 
in  the  air  breathed,  as  when  the  carbonic  acid  content  is 
abnormally  high,  materially  less  carbon  dioxide  is  thrown 
off.  In  the  experiments  with  the  fowls  cited  there  accumu- 
lated in  the  ventilation  chamber  a  very  large  amount  of 
moisture,  enough  not  only  to  wet  the  walls  so  that  it  ran 
down  the  sides  but  to  so  saturate  a  layer  of  dry  sand  which 
was  used  as  an  absorbent  as  to  cause  the  surface  to  appear 
wet. 

In  April,  1891,  we  conducted,  during  14  days,  an  experi- 
mental study  of  the  effect  of  ample  and  deficient  ventilation 
upon  20  milch  cows.  The  experiment  was  made  in  a  half- 
basement  stable,  represented  in  Fig.  19,  having  three  out- 
side doors,  thirteen  large  windows  and  a  door  leading  by 
a  stairway  to  the  floor  above.  The  ceiling  was  nine  feet 
above  the  floor  and  the  stable  contained  960  cubic  feet  of 
space  per  cow.  Leading  upward  from  the  ceiling  there  were 
two  hay  chutes  2  by  3  feet  in  cross  section,  20  feet  high, 
which  could  be  opened  or  closed  at  will,  and  a  ventilating 
flue,  12  by  16  inches,  terminating  near  the  ridge  of  the 
roof  inside.  The  experiment  consisted  in  closing  all  doors 
and  windows  and  the  two  hay  chutes,  leaving  only  the  ven- 
tilating shaft  open,  for  the  trials  under  insufficient  ventila- 
tion ;  and  in  leaving  both  hay  chutes  open,  together  with  the 
ventilating  flue,  for  good  ventilation. 

During  the  trial  the  cows  were  kept  continuously  in  the 
stable,  with  the  hay  chutes  closed  during  two  days  and  then 
with  them  open  two  days,  the  trials  being  repeated  four 


Ventilation  Experiment  with  Cows. 


29 


times.  Following  these  four  trials  the  hay  chutes  were 
closed  during  three  consecutive  days  for  poor  ventilation 
and  left  open  the  following  three,  making  14  days  in  all. 
The  feed  ojitcn.  tin'  water  drank,  the  milk  produced  and  the 


Pig.  19.— Stable  in  which  ventilation  experiment  was  conducted.  One  or 
more  hay  chutes,  with  no  ventilating  flue,  has  been  a  common  way  of 
ventilating  dairy  stables;  often  the  chutes  are  absent. 

cows  themselves  were  weighed  each  day.  It  was  found 
that  measurably  the  same  amount  of  feed  was  eaten  under 
both  conditions  of  ventilation.  But  during  the  days  of  in- 
sufficient ventilation  the  cows  drank,  on  the  average,  11.4 
pounds  more  water  each  daily  and  yet  lost  in  weight  an 
average  of  10.7  pounds  at  the  end  of  each  period,  regain- 
ing this  when  good  ventilation  was  restored,  and  this  too 
when  they  were  drinking  less  water.  During  the  good  ven- 
tilation days  too,  for  each  and  every  period,  the  cows  gave 
more  milk,  the  average  being  .  55  pounds  per  head  per  day. 


30  f  Ventilation. 

At  the  end  of  the  14  days  the  cows  were  turned  into  the 
yard  and  exhibited  an  intense  desire  to  scratch  and  lick 
their  sides  and  limbs,  doing  so  until  the  hair  in  many  cases 
was  stained  with  blood.  Examination  showed  that  during 
the  interval  a  rash  had  developed  which  could  be  felt  by 
the  hand  in  the  form  of  hard  raised  points  and  the  rasping 
of  these  off  caused  the  bleeding.  In  the  case  of  these  cows 
it  seems  clear  that  on  the  days  of  insufficient  ventilation 
conditions  existed  which  may  fairly  be  compared  with  those 
causing  the  smoking  in  the  lamp ;  the  reduced  supply  of  air 
in  the  stable  made  it  impossible  for  entirely  normal  chem- 
ical changes  to  take  place  in  the  body ;  it  was  impossible  for 
the  lungs  to  remove  the  waste  products  in  the  form  of  car- 
bon dioxide  to  as  great  an  extent  as  was  usual  and  it  seems 
highly  probable  that  because  of  this  some  of  the  waste  prod- 
ucts had  to  be  of  a  different  chemical  nature,  such  as  could 
be  eliminated  through  other  channels.  But  if  this  was  true 
a  stronger  action  on  the  part  of  the  kidneys  and  perhaps 
on  the  part  of  the  alimentary  canal  as  well,  which  created 
the  increased  demand  for  more  water  to  the  extent  of  11.4 
pounds  daily,  all  of  which  was  lost  and  enough  additional 
to  reduce  the  average  weight  10.7  pounds  by  the  close  of 
each  period,  would  seem  to  justify  the  conclusion,  not  only 
that  abnormal  chemical  changes  were  taking  place  in  the 
bodies  of  the  animals,  but  also  that  the  elimination  of  im- 
purities so  produced  was  not  occurring  in  the  usual  way. 
During  the  days  of  insufficient  ventilation  moisture  con- 
densed to  such  an  extent  on  the  walls  and  ceiling  as  to  drip 
and  run  down  the  sides ;  at  the  same  time  the  odor  was  very 
strong  and  the  air  depressing  to  one  coming  in  from  out- 
side. 

It  is  important  to  point  out  here  that  the  appointments 
of  the  stable  in  which  these  trials  were  conducted  are  typi- 
cal of  perhaps  a  majority  of  dairy  stables  in  the  United 
States  today ;  furthermore,  it  is  a  very  common  practice  to 
close  hay  chutes  and  similar  openings  during  cold  weather, 
especially  during  the  night,  thus  establishing  the  precise 
conditions  designated  in  this  experiment  as  poor  ventila- 


Volume  of  Air  Movement  Needful.  31 

tion  and  which  produced  the  observed  results.  The  damp- 
ness in  the  stable  due  to  condensation  of  moisture,  the  of- 
fensive odors  and  the  oppressive  character  of  the  air  which 
have  been  referred  to  as  occurring  in  the  experiment  de- 
scribed are  all  present  in  the  average  dairy  stable  in  greater 
or  less  intensity  wherever  ample  provision  is  not  definitely 
made  to  secure  proper  ventilation. 

VOLUME  OF   AIR   WHICH   SHOULD   MOVE   CONTINUOUSLY 
THROUHG  DWELLINGS  AND   STABLES. 

"Jane,  you  and  Ellen  go  up  and  do  the  chamber  work 
and  be  sure  to  open  the  windows  and  give  the  rooms  a  good 
airing."  Yes,  indeed,  but  why  not  a  better  airing  during 
all  the  night  when  the  sleepers  are  occupying  the  beds. 
Certainly  a  refreshing  drink  direct  from  the  spring,  and  a 
full  supper  from  the  dining  room,  easily  satisfy  all  crav- 
ings from  an  early  to  bed  to  a  late  to  rise.  And  will  not 
a  full  breath  or  at  least  a  half  hour  of  them,  when  drawn 
from  the  park  or  from  the  pasture,  as  fully  meet  the  needs 
of  a  night?  Perhaps  Mother's  caution  does  imply  this  or 
was  it  her  remembrance  of  a  weary  waking  from  an  unre- 
freshing  sleep;  a  mother's  feeling  that  something  surely 
ought  to  be  done  and  she  would  faithfully  do  the  little  that 
lay  in  her  power?  Or  is  the  idea  really  prevalent  that  to 
have  the  chamber  full  of  outdoor  air  to  start  with  will  gen- 
erally meet  the  requirements  of  the  night  ? 

It  is  difficult  for  many,  and  perhaps  for  most  people,  to 
harmonize  their  own  experience  in  this  matter  of  ventila- 
tion with  those  who  advocate  the  imperative  need  of  special 
provision  to  secure  ventilation,  as  it  seems  clear  that  since 
no  such  provisions  are  generally  made  for  either  dwellings 
or  stables  and  since  no  serious  consequences  have  certainly 
resulted  which  are  ascribed  to  the  lack  of  such  provisions 
they  can  hardly  be  regarded  as  necessary.  For  all  such  let 
them  be  urged  to  reflect  that  the  animal  mechanism  posses- 
ses a  marvelous  power  of  endurance  and  for  the  tolerance 
of  conditions  even  seriously  injurious  and  that  usually  the 


32  Ventilation. 

existence  of  such  pending  troubles  are  not  recognized  until 
it  is  too  late  and  that  even  when  they  are  recognized  their 
true  cause  may  remain  unknown.  Above  all  should  it  be 
emphasized  and  ever  borne  in  mind  that  there  is  an  ex- 
tremely wide  range  in  the  powers  of  endurance  of  foul  air, 
not  only  among  different  animals,  but  among  individuals 
of  the  same  species,  so  that  wherever  more  than  one  is  oc- 
cupying a  compartment  the  degree  of  air  purity  must  cer- 
tainly be  such  as  to  meet  the  needs  of  the  least  tolerant  oc- 
cupant. Not  only  does  the  lung  capacity  of  individuals 
vary  but  the  depth  of  respiration  is  very  different  owing 
to  difference  in  habit  or  difference  in  dress,  thus  making  it 
impossible  for  all  to  derive  the  same  amount. of  oxygen,  or 
eliminate  the  same  amount  of  carbon  dioxide  under  like 
conditions  of  air.  Such  differences  are  of  course  exag- 
gerated in  all  cases  where  the  lung  capacity  is  reduced  on 
account  of  disease. 

When  the  breath  is  forced  into  a  cold  lamp  chimney  or 
glass  vessel  there  is  at  once  perceptible  a  marked  condensa- 
tion of  moisture  on  the  walls,  showing  that  very  material 
quantities  of  moisture  are  being  discharged  in  invisible 
form  into, the  air.  So  too,  if  the  hand  is  placed  for  a  sec- 
ond with  the  palm  against  the  cold  surface  of  a  mirror 
and  removed  before  the  surface  has  been  warmed  there  will 
be  apparent  in  this  case  also  a  marked  condensation  of 
moisture,  showing  that  not  only  from  the  lungs  but  from 
the  skin  as  well  the  air  of  compartments  is  being  contin- 
ually charged  with  moisture.  In  the  case  of  man  the  mean 
amount  of  moisture  exhaled  from  the  lungs  and  transpired 
by  the  skin  is  placed  by  Seguin  at  1,080  grains  per  hour, 
the  minimum  being  486  and  the  maximum,  except  under 
very  unusual  conditions,  1,458  grains  per  hour.  This 
moisture  discharged  into  the  air  of  a  compartment  in  which 
no  change  is  taking  place  tends  rapidly  to  saturate  it,  soon 
bringing  it  to  a  point  where  moisture  condenses  on  the 
walls.  If  we  would  not  have  this  moisture  condensation 
there  must  necessarily  be  a  movement  of  air  through  the 


Removal  of  Perspired  and  Exhaled  Moisture.        33 

room  sufficient  in  volume  to  carry  away  the  moisture  as 
rapidly  as  it  is  formed. 

The  ability  of  air  to  carry  moisture  under  given  condi- 
tions of  temperature  and  pressure  is  very  definitely  known  ; 
hence  it  becomes  possible  to  compute  the  volume  of  air 
which  must  pass  through  any  compartment  where  a  known 
amount  of  moisture  is  being  thrown  into  the  air,  in  order 
that  this  moisture  may  be  carried  away  as  rapidly  as 
formed.  The  following  table  has  been  computed  from  Se- 
guin's  data,  using  the  Smithsonian  table  167  giving  the 
capacity  of  air  for  moisture. 

Volume  of  ////•  76  pear  cent  .«<if«r«f<>d  at  40°,  50°,   nip.  ,/„,/  ?o°  p.  re- 
quvred  when  leaving  the  room  saturated  at  /vy°,  /<>  removt    tin    ////?,/- 

//mni.  nr,r<i</i   ,nnl  nni,  /•/'///  /////  nnnni  nt  of  ///»/*////•/   thmir,,    off  from  1li< 
hi  tit  i*  dint  >•/•///  /a  r  hour,  hi/ 


When  tht'  temperature  of  the  incoming  air  K 

40°  50°  60°  70° 

Tlit-  required  hourly  movement  of  air  i>. 


(TU.  ft. 

cu.  ft. 

cu.  ft. 

cu.  ft. 

Minimum  

83 

99 

132 

244 

A  ve  nitre 

185 

.).),, 

294 

541 

Maximum  

250 

296 

397 

731 

From  this  table  it  is  seen  that  in  order  to  remove  from 
a  compartment  the  moisture  thrown  into  its  air  as  invisible 
vapor  from  the  lungs  and  skin,  so  as  to  avoid  oversatura- 
tion,  there  must  be  moved  through  it  each  hour  more  than 
185  cubic  feet,  220,  294  or  541  cubic  feet  on  the  average  for 
each  occupant,  according  as  the  air  enters  at  40°,  50°,  60° 
or  70°  F.,  the  air  at  the  same  time  passing  out  fully  sat- 
urated at  70°.  It  is  clear,  therefore,  in  order  that  dwellings 
and  especially  schoolhouses,  churches  and  stables  may  have 
a  reasonably  dry  atmosphere  there  must  be  a  large  and 'con- 
tinuous air  movement  through  them  which  is  proportioned 
to  the  number  of  occupants. 

From  the  recent  studies  of  Dr.  Armsby  it  was  determined 
that  a  1,000-pound  steer  charges  the  air  of  the  stable  with 


34  Ventilation. 

invisible  vapor,  from  skin  and  lungs,  to  the  extent  of  no 
less  than  10.4  pounds  daily.  In  order,  therefore,  that  a 
dairy  stable  of  twenty  cows  may  not  have  the  moisture  con- 
densed on  its  walls  there  must  be  an  air  movement  through 
it  continuously  sufficient  to  remove  208  pounds  daily;  for 
40  cows  it  must  be  sufficient  to  remove  416  pounds ;  for  60, 
624  pounds;  for  80,  832  pounds  and  for  100  cows  there 
must  be  a  movement  which  will  carry  from  the  stable 
through  the  out-going  air,  as  invisible  vapor,  1,040  pounds, 
or  more  than  half  a  ton,  of  moisture  daily.  The  mean 
amount  of  moisture  carried  by  the  air  in  most  parts  of  the 
United  States  at  7  A.  M.  is  seldom  less  than  70  per  cent  of 
its  full  saturation  capacity.  In  the  next  table  there  are 
given  the  volumes  of  air  per  hour  and  per  cow  which  must 
pass  through  a  stable  in  order  to  prevent  condensation. 

Required  number  of  cubic  feet  of  air,  per  hour  and  per  head,  to  pre- 
vent condensation  of  moisture  when.it  enter*  t//r  *t<ible  75  per  cent, 
saturated  and  leaves  it  saturated  at  the  stable  temperature. 


If  the  outside  air  is 
75  per  cent  saturated 
at  the  temp,  of 

When  the  stable  temperature  is, 
30°                   40°                  50°                  60°                 70° 
The  volume  of  air  per  head  and  per  hour  must  be, 

—10°  F  .  .  . 

cu.  ft. 
1,788 
1,982 
2,334 
2,620 
3,140 
6,228 

cu.  ft. 
1,164 
1,253 
1,385 
1,489 
1.634 
2.201 
4,268 

cu.  ft. 
792 
832 
887 
931 
996 
1,185 
i  .  :><H) 

1,782 

cu.  ft. 
540 
554 
569 
(514 
638 
715 
842 
1,126 

cu.  ft. 
394 
402 
415 
424 
434 
466 
520 
655 

0° 

10°  

15°  

20°  

30°  .. 

40° 

50°  .  

This  table  makes  it  clear  that  in  dairy  stables  a  large  and 
continuous  movement  of  air  through  them  is  imperative 
simply  to  prevent  the  condensation  on  the  walls  of  the 
moisture  of  perspiration  and  respiration ;  and  the  damp- 
ness so  often  observed  in  basement  stables  is  a  proof  posi- 
tive of  the  too  slow  rate  of  change  of  air  in  them  to  even 
carry  out  the  moisture.  When  the  outside  air  containing 
three-fourths  of  all  the  moisture  it  can  retain  at  a  tem- 
perature' of  0°  enters  a  stable  which  is  maintained  at  70° 
F.,  then  402  cubic  feet  per  cow  must  enter  and  leave  the 


Volume  of  Air  Required  to  Remove  Moisture.         35 

stable  each  hour  to  completely  remove  all  the  moisture 
thrown  off  by  the  skin  and  lungs.  If  the  stable  tempera- 
ture is  maintained  at  60°  instead  of  at  70°  then  the  air  move- 
ment must  be  at  the  rate  of  554  cubic  feet;  if  at  50°,  832 
cubic  feet;  if  at  40°,  1,253  cubic  feet,  and  if  the  stable 
temperature  is  as  low  as  30°  then,  with  the  air  entering  the 
stable  three-fourths  saturated  at  0°,  no  less  than  1,982 
cubic  feet  of  air  must  enter  and  leave  the  stable  for  each 
cow  each  hour.  And  so  if  the  outside  air  is  three-fourths 
saturated  at  20°  and  the  stable  temperature  is  maintained 
at  70°,  the  necessary  air  movement,  to  keep  the  stable  dry, 
is  434  cubic  feet  per  hour  and  per  cow;  but  if  the  stable 
temperature  is  60°  then  the  amount  must  be  638  cubic 
feet;  if  50°,  then  996  cubic  feet;  if  40°,  then  1,634  cubic 
feet ;  while  if  the  stable  is  as  cold  as  30°  then  the  air  change 
must  be  at  a  rate  exceeding  3,140  cubic  feet  per  hour  and 
per  cow  to  carry  away  the  moisture  thrown  off.  These  last 
statements  mean  that  when  20  cows  are  housed  in  a  stable 
with  a  floor  space  20  by  40  feet  and  with  9  foot  ceiling  this 
entire  volume  of  air  must  be  changed  once  every  50  minutes 
when  the  stable  temperature  is  70°  ;  once  every  33  minutes 
when  the  temperature  is  at  60°  once  every  21  minutes  if  it 
is  at  50°  once  every  13  minutes  if  it  is  at  40°  and  if  the 
stable  temperature  is  as  low  as  30°  then  the  entire  volume 
of  air  in  the  stable  must  be  changed  as  often  as  every  7 
minutes  in  order  to  prevent  moisture  condensation.  It  is 
thus  seen  that  the  lower  the  temperature  of  the  stable  and 
the  higher  the  temperature  of  the  outside  air  before  enter- 
ing the  stable  the  larger  must  be  the  air  movement  through 
it  in  order  to  carry  away  all  the  moisture  exhaled  by  the 
animals. 

But  large  as  must  be  the  air  movement  through  stables 
simply  to  keep  them  dry  this  is  not  sufficient  to  maintain 
the  required  purity  of  air  to  meet  the  needs  of  the  animals 
themselves  either  in  the  oxygen  supply  or  in  the  removal  of 
carbon  dioxide  and  the  poisonous  volatile  organic  products 
exhaled  by  them.  It  must  be  held  of  the  highest  import- 
ance, from  the  standpoint  of  house  and  stable  sanitation, 


36  Ventilation. 

that  some  standard  of  air  purity  should  be  experimentally 
determined  so  that  the  rate  of  air  supply  for  each  individ- 
ual, which  constitutes  adequate  ventilation,  shall  be  def- 
initely known  and  shall  be  used  in  house  and  stable  con- 
struction in  making  definite  provision  for  adequate  ventila- 
tion. 

De  Chaumont  has  assumed  a  standard  of  purity  of  air  for 
man  of  99.51  per  cent,  which  means  that  the  carbon  dioxide 
in  the  air  of  a  room  due  to  respiration  should  not  be  aug- 
mented more  than  two  parts  in  ten  thousand  over  that  car- 
ried by  pure  air,  or  more  than  .02  volume  per  cent.  This 
limit,  too,  is  found  by  direct  observation  to  be  that  at  which 
the  sense  of  smell  fails  to  detect  the  odor  of  ' '  closeness ' '  in 
an  occupied  room.  Carnelly,  Haldane  and  Anderson  admit 
a  standard  of  purity  much  lower  than  this  and  it  is  com- 
monly held  that,  for  man,  when  the  air  of  a  room  contains 
no  more  than  .07  volume  per  cent  of  carbon  dioxide  it  is 
sufficiently  pure  for  the  purposes  of  respiration.  In  using 
the  carbon  dioxide  as  a  standard  it  is  held  by  writers  on 
ventilation,  not  that  more  or  less  of  this  would  be  injurious, 
but  rather  that  this  amount  of  carbon  dioxide  is  an  index 
of  the  degree  at  which  the  "crowd  poisons"  have  become 
sufficiently  concentrated  to  be  injurious.  We  feel  that  it 
may  quite  as  likely  express  the  degree  of  oxygen-exhaus- 
tion at  which  the  more  sensitive  occupants  of  a  room  begin 
to  feel  the  depressing  effect  of  an  insufficient  supply  of 
oxygen  in  the  system,  and  the  time  at  which  deeper  breath- 
ing needful  to  compensate  for  exhaustion  becomes  a  con- 
scious effort.  De  Chaumont 's  standard  of  purity  requires 
an  air  movement  of  one  cubic  foot  per  second  for  each  adult 
man  when  at  rest,  or  3,600  cubic  feet  per  hour.  Men  in 
active  labor  would  require  more,  while  women  and  children 
at  rest  would  need  somewhat  less.  The  other  standard  of 
purity  would  require  an  air  movement  of  about  1,800  cubic 
feet  per  hour  for  an  adult  man  at  rest  and  would  hold  the 
composition  of  the  air  of  the  room  at  99  parts  pure  and 
one  part  at  the  degree  of  exhaustion  of  once-respired  air, 
and  in  this  condition  its  oxygen  content  would  be  reduced 


Leakage  of  Air  Through  Stable  Walls.  37 

from  20.582  volume  per  cent,  as  stated  in  the  table  for 
moist  air,  page  13,  to  20.529  per  cent,  an  exhaustion  of  its 
oxygen  content  amounting  to  .05  volume  per  cent  of  the  air 
and  of  .26  per  cent  of  the  oxygen  itself.  De  Chaumont's 
standard  of  purity  would  permit  exhaustion  to  but  one  half 
of  these  amounts. 

In  dealing  in  a  practical  way  with  problems  of  ventila- 
tion, providing  means  for  the  entrance  into  and  exit  of  air 
from  dwellings  and  stables,  it  is  necessary  to  take  into  ac- 
count the  openness  of  structure  which  is  unavoidable  under 
present  methods  and  materials  of  construction,  for  the  rea- 
son that  in  consequence  of  this  openness  of  structure  there 
results  a  not  inconsiderable  air  movement  into  and  out  of 
compartments  through  openings  not  intentionally  provided, 
and  which  does  much  toward  providing  the  necessary  air 
supply,  even  when  the  wind  movement  outside  is  small. 
That  material  changes  of  air  do  take  place  through  the 
walls  of  buildings  we  have  abundant  proof,  and  experi- 
ments conducted  at  the  Geneva  Experiment  Station,  N.  Y. 
furnish  a  basis  for  computing  what  this  rate  of  movement 
was  under  one  set  of  conditions.  The  stable  in  question  had 
a  floor  space  of  51  by  33  feet  with  a  9  foot  ceiling,  accom- 
modating at  the  time  22  cows.  Doctor  Jordan  was  having 
a  study  made  of  the  distribution  of  carbon  dioxide  in  the 
stable  air  and  during  one  set  of  observations,  when  the 
ventilators  were  open,  the  mean  content  of  carbon  dioxide 
was  found  to  be  .462  volume  per  cent,  -.534  per  cent  near 
the  ceiling,  .501  at  a  middle  level  and  .351  near  the  floor. 
If  we  may  take  the  composition  of  once-respired  air  in  this 
case  at  the  value  given  in  the  second  part  of  the  table,  page 
14,  and  the  amount  of  air  breathed  per  hour  and  per  cow  at 
116.8  cubic  feet,  page  9,  the  degree'  of  purity  of  air  in 
this  stable  must  have  been  at  the  time  89.72  per  cent  and 
air  must  have  been  entering  and  leaving  it  at  the  rate  of 
some  24,995  cubic  feet  per  hour,  or  1,136  cubic  feet  per  cow. 
When  the  ventilators  of  this  stable  were  closed,  however, 
the  carbon  dioxide  present  in  the  air  had  increased  so  as  to 
be  1 . 40  volume  per  cent  near  the  ceiling,  1 . 236  per  cent  at 


38  Ventilation. 

a  middle  level  and  1.034  per  cent  near  the  floor,  making  an 
average  of  1.2233  volume  per  cent.  On  the  same  basis  of 
calculation  as  used  above  air  in  this  case  must  have  been 
entering  and  leaving  the  stable  at  a  rate  of  some  9,059  cubic 
feet  per  hour,  which  is  nearly  412  cubic  feet  per  cow,  and 
the  air  in  the  stable  at  this  time  had  a  degree  of  purity  ap- 
proximating 71.63  per  cent,  which  means  a  reduction  of 
the  oxygen  content  to  19 . 13  volume  per  cent,  a  lowering  be- 
low that  of  standard  air  of  1 . 36  per  cent.  We  have,  there- 
fore, in  this  case,  a  dairy  stable  accommodating  22  cows, 
built  close  for  warmth  and  having  all  its  special  provisions 
for  ventilation  closed,  yet  with  air  entering  and  leaving 'it 
at  the  rate  of  more  than  9,000  cubic  feet  per  hour,  the  air 
being  changed  in  the  stable  as  often  as  once  in  every  100 
minutes,  whereas,  when  both  the  intentional  and  uninten- 
tentional  facilities  for  interchange  of  air  were  in  operation 
the  air  of  the  stable  was  changed  once  in  about  every  36 
minutes. 

At  the  Minnesota  Experiment  Station  experiments  were 
conducted  which  furnish  another  basis  for  making  a  similar 
estimate  regarding  the  permeability  of  stable  walls  to  air. 
In  this  case  a  steer  was  kept  during  varying  intervals  of 
time  in  a  closed  stall  having  a  capacity  of  784  cubic  feet 
with  one  outside  wall  and  a  single  window.  The  stall  was 
provided  with  a  cement  concrete  floor,  the  walls  were  of 
hard  brick  and  the  ceiling  of  boards,  which  was  covered 
with  heavy  muslin,  this  and  the  walls  being  painted  to  ren- 
der them  more  nearly  air  tight.  The  window  and  a  door 
opening  into  a  hallway  were  close  fitting  and  the  door  was 
so  arranged  as  to  permit  the  animal  to  be  fed  and  watered 
without  opening  the  door,  the  animal  being  cared  for  with- 
out the  attendant  entering  the  stall  except  at  the  close  of 
an  experiment.  Under  these  conditions  there  was  a  wide 
variation  in  the  composition  of  the  air  in  the  stall,  the  data 
showing  a  range  between  .52  and  2.67  volume  per  cent,  of 
C02.  The  authors  say  "After  the  work  had  been  in  prog- 
re'ss  for  a  short  time  the  windows,  walls  and  ceiling  became 
-covered  with  water  which  at  times  ran  down  the  walls  and 


Leakage  of  Air  in  Minnesota  Stable.  39 

from  the  ceiling.  The  quantity  varied  with  the 
condition  of  the  weather.  After  the  stall  had  been  closed 
several  days  at  the  beginning  of  Series  B  mould  began  to 
appear  on  the  walls  and  gradually  increased  until  almost 
the  entire  wall  surface  was  covered.  After  the  closed  stall 
was  in  use  several  weeks  it  was  noticed  that  the  paint  was 
softened  in  several  places  on  the  wall  and  running  down 
with  the  water.  This  continued  until  almost  the  entire 
wall  surface  was  bare  of  paint." 

"After  entering  the  closed  stall  at  the  close  of  a  period 
to  make  a  reading  or  remove  an  animal  one  was  forcibly 
impressed  by  a  stifling  air,  its  excessive  moisture  and  the 
apparently  high  temperature.  The  first  few  minutes  one 
invariably  had  difficulty  in  breathing,  this  soon  passed 
away,  and  he  began  to  sweat,  and  feel  uncomfortably 
warm.  This  condition  did  not  last  long,  perhaps  five  min- 
utes, after  which  no  unpleasant  effects  were  noticed.  After 
leaving  the  stall  the  outside  air  seemed  cold  and  so  light 
that  one  involuntarily  took  several  very  deep  inspirations. 
The  odor  of  manure  did  not  become  sufficiently  strong  to  be 
offensive  even  at  the  close  of  a  10-day  period." 

"We  have  here  what  would  appear  to  be  extreme  condi- 
tions as  to  closeness  of  construction ;  conditions  under  which, 
steers  were  kept  and  fed  continuously  without  leaving  the 
stable  and  without  having  the  door  opened,  except  the  slide 
through  which  feed  was  quickly  introduced,  for  periods, 
in  one  case,  as  long  as  28  days ;  conditions  in  which  the  ex- 
perimenter thought  the  animals  did  not  seriously  suffer 
from  the  effects  of  insufficient  ventilation ;  but  conditions 
which  the  experimenter  himself  invariably  found  oppres- 
sive, as  he  has  described  above,  on  entering  the  stall  at  the 
close  of  an  experiment.  It  seems  quite  clear  from  the  anal- 
yses of  the  stable  air  which  were  made  that  there  must  have 
been  a  very  considerable  air  movement  through  the  stable 
at  all  times  whenever  there  was  a  considerable  wind  move- 
ment outside.  Taking  the  average  weight  of  the  animals 
experimented  with  at  600  pounds  and  assuming  a  respiration 
volume  proportional  to  this  weight  and,  further,  that  the 


40  Ventilation. 

consumption  of  oxygen  and  excretion  of  carbon  dioxide  oc- 
curred in  the  normal  ratio,  we  may  calculate  the  air  move- 
ment through  this  stall  by  the  same  method  used  in  the  case 
of  the  dairy  stable.  When  such  a  calculation  is  made  a  .  52 
volume  per  cent  of  carbon  dioxide  maintained  in  the  stall 
air  requires  a  continuous  flow  at  the  rate  of  some  591  cubic 
feet  per  hour,  and  when  the  content  of  carbon  dioxide  was 
maintained  at  2 . 67  per  cent  an  exchange  of  air  is  required 
at  a  rate  not  less  than  about  112  cubic  feet  per  hour.  It 
must  not  be  understood  that  the  values  here  computed,  re- 
lating either  to  this  stall  or  to  the  dairy  barn  which  has 
been  considered,  have  more  than  an  approximate  degree  of 
accuracy.  They  undoubtedly  do  express  a  general  and  im- 
portant truth,  namely,  that  material  volumes  of  air  do  enter 
and  leave  what  are  regarded  as  closely  constructed  dwell- 
ings and  stables  by  means  of  openings  not  specially  pro- 
vided, and  that  the  amount  of  such  movement  varies  be- 
tween extremely  wide  limits,  as  must  have  been  the  case  in 
the  Minnesota  stall,  the  ventilation  being  best  when  the 
wind  movement  is  greatest  outside.  It  is  clear  however, 
from  the  data  presented  in  this  connection,  that  even  under 
the  best  of  outside  conditions  close  stable  and  dwelling  con- 
struction can  seldom  give  adequate  ventilation,  certainly 
never  at  times  when  the  air  is  still. 

The  experiments  conducted  at  the  Minnesota  Experiment 
Station  lead  the  authors  to  say:  "Cattle  seem  to  thrive 
under  what  are  apparently  the  worst  possible  conditions  of 
stabling.  Beef  cattle  fatten  well  and  dairy  records  are 
made  in  stables  that  are  simply  abominable  from  recognized 
standards  of  good  stabling.  *  *  * 

' '  Stable  ventilation  in  our  northern  states  during  our 
long  cold  winters  is  a  difficult  problem  at  best.  To  get  any- 
thing like  the  amount  demanded  by  most  authorities  is  cer- 
tainly impracticable.  If  less  is  compatible  with  the  health 
and  comfort  of  our  confined  stock  it  is  very  important  that 
we  know  it  and  be  quite  sure  of  it.  If  what  we  call  moder- 
ately or  even  decidedly  foul  stable  air  is  not  commonly  in- 
imical to  the  health  and  comfort  of  these  animals  or  to  the 


Ventilation  Problem  Stated.  41 

owner's  profits  then  it  is  of  the  utmost  importance  that  we 
know  this  also.    *    *    * 

* '  The  real  problem  with  which  we  have  to  finally  deal  is, 
how  little  air  is  compatible  with  normal  health  and  comfort 
of  the  stock  and  with  economic  feeding. ' ' 

It  is  very  unfortunate  that  language  like  this  should  find 
a  place  in  the  instructional  literature  of  animal  husbandry 
for  it  is  certainly  much  nearer  the  truth  and  conducive  to 
a  safer  practice  to  say :  The  real  problem  with  which  we 
have  finally  to  deal  is  how  nearly  can  we  maintain  the  air 
of  dwellings  and  stables  at  the  normal  out-of-door  fresh  air 
purity  with  practicable^conomy.  It  has  certainly  never 
been  a  maxim  of  good  feeders  to  supply  the  smallest  ration 
"compatible  with  the  normal  health  and  comfort  of  the 
stock  and  with  economic  feeding. ' '  Rather  has  it  been  the 
practice  to  place  before  the  animals  the  largest  amount  of 
feed  they  can  possibly  be  urged  to  eat  and  return  a  good 
profit.  A  like  maxim  must  lead  in  the  supply  of  air  which 
constitutes  more  than  two-thirds  of  every  adequate  ration. 

In  our  study  of  stable  conditions  and  of  the  possibilities 
of  air  supply  we  have  been  led  to  the  conviction  that  an  air 
movement  through  the  stable  can  and  should  be  secured 
which  will  maintain  a  degree  of  purity  not  lower  than  96 . 7 
per  cent ;  that  the  air  of  stables  and  dwellings  should  at  no 
time  contain  more  than  3.3  per  cent  of  air  once  breathed. 
Such  an  air  movement  as  this  is  entirely  practicable  in  the 
stables  of  cold  climates  and  a  much  higher  rate  is  possible 
in  every  properly  heated  dwelling. 

In  order  that  the  air  of  a  stable  shall  at  no  time  contain 
more  than  3.3  per  cent  of  air  once  breathed  it  must  enter 
and  leave  at  the  rate  of  4,296  cubic  feet  per  hour  and  per 
head  for  horses,  at  the  rate  of  3,542  cubic  feet  for  cows,  of 
1,392  cubic  feet  for  swine,  of  917  cubic  feet  for  sheep  and  of 
35  cubic  feet  per  hour  for  hens,  on  the  average.  In  the  case 
of  man  the  amount  of  air  breathed  per  hour  is  17 . 71  cubic 
feet  and  the  hourly  movement  through  the  dwelling  and 
sleeping  room,  in  order  to  maintain  the  degree  of  purity 
stated,  needs  to  be  not  less  than  537  cubic  feet  for  each  adult. 


42 


Ventilation. 


These  several  amounts  are  graphically  represented  in  Figs. 
20  and  21.  | 

To  secure  an  air  movement  through  a  cow  stable  contain- 
ing 20  cows  a  ventilating  flue  2  feet  by  2  feet  is  required 
through  which  the  air  moves  at  the  rate  of  295  feet  per 
minute.  .  A  flue  of  this  size,  too,  will  be  required  for  17 


Fig.  20.— Each  drawing  represents  the  volume  of  air  which  should  enter 
and  leave  the  stable  or  room  during  each  hour  for  each  adult  occu- 
pant. Each  square  represents  a  square  foot  and  the  subdivisions 
Indicate  the  number  of  cubic  feet  in  each  room. 

horses,  for  51  pigs  and  for  77  sheep.  Double  the  number 
of  animals  named  will  require  ventilating  flues  having 
nearly  double  the  cross  section  stated  while  smaller  num- 
bers would  require  flues  relatively  larger  in  proportion  on 
account  of  the  relatively  greater  friction  in  small,  as  com- 
pared with  that  in  large  flues. 

To  emphasize,  we  wish  again  to  state  that  it  is  a  matter 
of  the  highest  economic  and  sanitary  importance  that  rigid 


Volume  of  Air  Required  Hourly. 


43 


experiments  should  be  instituted,  both  for  man  and  for  do- 
mestic animals,  which  shall  establish  beyond  all  doubt  what 
is  an  entirely  sufficient  degree  of  air  purity  for  dwellings 
and  for  stables  to  the  end  that  a  safe  basis  may  be  had  upon 
which  to  specifically  provide  proper  and  fully  adequate 
means  for  ventilation.  It  is  important  to  recognize  that  the 


Fig.  21.— Each  drawing  represents  the  volume  of  air  which  should  enter 
and  leave  the  stable  during  each  hour  for  each  adult  occupant.  The 
rulings  indicate  the  number  of  cubic  feet  in  each  room,  each  square 
is  one  foot. 

standard  of  air  purity  here  assumed  is  materially  below 
that  which  admits  a  content  of  carbon  dioxide  in  the  air  of 
a  room  of  .07  volume  per  cent.  Indeed  the  standard  as- 
sumed for  stables  permits  a  content  of  carbon  dioxide  as 
high  as  .167  volume  per  cent,  a  quantity  more  than  double 
that  above ;  and  it  is  important  to  say  again  here,  for  com- 
parison, that  Doctor  Jordan  found  in  his  stable,  with  the 
ventilation  system  in  operation,  a  carbon  dioxide  content  as 
high  as  .462  volume  per  cent,  which  is  nearly  three  times 
that  of  the  standard  we  have  assumed  for  stables.  In  his 


44  Ventilation. 

case  the  degree  of  air  purity  was  89.67  volume  per  cent  in- 
stead of  96.7  which  we  have  assumed  as  a  probably  safe 
limit.  Should  it  be  found  admissible  to  tolerate  in  a  stable 
5  to  10  per  cent  of  air  once  breathed,  instead  of  3.3  per 
cent,  which  is  here  assumed,  such  a  degree  of  purity  could 
be  more  readily  secured  under  all  conditions  of  weather. 
We  feel  that  it  would  be  .unwise,  however,  to  adopt  a  lower 
standard,  in  advance  of  definite  knowledge,  in  stable  con- 
struction for  the  reason  that  it  is  a  very  simple  matter  to 
reduce  the  air  movement  through  a  stable  when  the  large 
capacity  of  the  ventilating  system  causes  the  rate  of  change 
to  be  too  high.  If  the  capacity  of  the  system  is  too  small 
there  is  no  help  except  that  of  resorting  to  open  windows  or 
similar  devices  which  are  undesirable  in  cold  weather,  par- 
ticularly if  it  is  windy. 


PEIXCIPLES  OF  VENTILATION. 


The  installation  of  a  satisfactory  system  of  ventilation  re- 
quires (1)  The  choice  of  a  proper  unit  of  air  movement; 
(2)  the  application  of  the  laws  and  principles  governing 
air  movement ;  (3)  and  the  adoption  of  proper  construction 
with  adequate  motive  power  to  insure  the  required  supply 
of  air.  There  can  be  no  proper  ventilation  for  dwelling  or 
stable  unless  into  it  and  out  of  it  there  is  a  continuous  flow 
of  air  at  some  proper  unit  rate.  It  has  been  pointed  out 
that  some  have  adopted  as  this  proper  unit  for  man  a  cubic 
foot  of  air  per  second;  that  others  have  accepted  one  half 
this  volume  as  adequate ;  and  that  we  have  taken  as  possibly 
sufficient  for  the  cow  3,542  cubic  feet  per  hour.  Without 
contending  that  either  of  these  units  is  the  best  it  must  be 
insisted  that  some  unit  should  be  chosen  and  then  adequate 
provision  made  to  secure  at  least  this  amount.  It  should 
be  recognized,  too,  that  in  increasing  the  air  movement  be- 
yond the  standard  chosen  there  is  little  chance  that  injuri- 
ous physiological  effects  will  follow  as  the  result  of  such 
choice  provided  a  proper  temperature  is  at  the  same  time 
maintained. 

Unnecessary  expense  of  installation  and  maintenance  is 
about  the  only  chance  for  mistake  against  which  to  guard; 
and  in  the  matter  of  expense  it  should  be  remembered  that 
where  the  forces  which  maintain  the  air  movement  through 
the  ventilated  space  are  the  wind  and  the  waste  heat  of  oc- 
cupants or  of  heating  and  lighting  appliances  the  cost  of  a 
ventilating  system  above  the  standard  capacity  will  be  only 
that  required  to  incorporate  a  somewhat  larger  amount  of 
material  in  its  construction.  It  is  the  part  of  wisdom, 
therefore,  to  install  a  ventilating  system  whose  capacity 
shall  be  abundantly  large. 


46  Ventilation. 

The  maintenance  of  a  flow  of  air  through  a  building  re- 
quires the  continuous  expenditure  of  energy  and  the 
amount  of  this  energy  and  of  work  done  will  be  in  direct 
proportion  to  the  weight  of  air  moved  through  the  venti- 
lated space  and  the  resistance  it  is  necessary  to  overcome  in 
accomplishing  this  movement.  If  the  air  of  an  audience 
room  occupied  by  1,000  persons  is  supplied  at  the  rate  of 
537  cubic  feet  per  hour  and  per  capita  the  work  to  be  done 
is  approximately  that  of  moving  some  21  *  tons  of  air 
through  the  room  each  hour. 

If  De  Chaumont's  standard  of  one  cubic  foot  of  air  per 
second  and  per  person  is  adopted  then  the  amount  of  work 
to  be  done  is  that  needed  to  move  through  the  room  144 2 
tons  of  air. 

So,  too,  if  a  herd  of  100  dairy  cows  is  to  be  supplied  with 
air  at  the  rate  of  3,542  cubic  feet  per  head  and  per  hour  the 
necessary  amount  of  work  is  that  of  moving  through  the 
stable  each  hour  14  tons,8  which,  if  the  air  is  forced 
through  vertical  shafts  40  feet  in  length,  of  ample1  capac- 
ity, represents  about  one-half  horse  power. 

POWER  USED  IN  VENTILATION. 

The  motive  power  commonly  utilized  in  ventilation  is  (1) 
the  passing  wind;  (2)  heat  generated  within  the  space  to 
be  ventilated  by  its  occupants,  by  lights  and  by  fires;  (3) 
rotary  fans  driven  by  one  or  another  source  of  power;  (4) 
and  steam  jets  or  coils  in  ventilation  flues.  By  whatever 
source  of  power  the  air  movement  for  the  purposes  of  ven- 
tilation is  effected  this  results  from  a  difference  of  pressure 
established  between  the  air  in  the  space  to  be  ventilated  and 
that  outside,  and  this  difference  of  pressure  is  the  immedi- 


537  X  =  21.48  tons. 


X^X-08    =144ton, 
-   =  14.168  tons. 


Motive  Power  in  Ventilation.  47 

ate  cause  of  air  movement  into  and  out  of  the  ventilated 
space. 

When  the  wind  has  its  progress  arrested  or  checked  by  a 
building  pressure  is  developed ;  this  pressure  tends  to  force 
air  through  any  pores,  chinks  or  openings  which  may  exist 
in  the  wall.  But  if  air  is  forced  into  the  building  that  in- 
side will  be  placed  under  a  greater  pressure  and  this 
greater  pressure  will  force  a  flow  outward  on  the  leeward 
side  or  upward  through  any  chimney  or  ventilating  shaft 
which  may  exist.  All  are  familiar  with  the  existence  of  a 
much  stronger  current  passing  around  the1  corner  of  a 
building  on  a  windy  day  than  is  found  at  a  distance  be- 
yond. This  higher  wind  velocity  is  proof  of  the  increased 
pressure  which  has  resulted  from  the  check  to  its  onward 
progress  it  has  received  from  the  building  and  this  must 
assist  in  the  ventilation  of  all  buildings  whose  walls  are  not 
absolutely  air  tight. 

The  pressure  of  the  wind  on  a  building,  and  therefore 
the  "head"  which  tends  to  force  air  into  it,  when  the  im- 
pact is  at  a  right  angle,  has  been  found  to  be  approximately 
given  by  the  two  equations 

Pressure  or  Head  =  .005  V8  or 
Pressure  or  Head  =  .00096  V2 

where  Y  is  the  velocity  of  the  wind  in  miles  per  hour,  the 
result  being  in  pounds  per  square  foot  of  surface  in  the  first 
equation,  and  in  inches  of  water  in  the  second.  These 
equations  mean  that  if  a  wind  is  blowing  at  the  rate  of  five 
miles  per  hour  against  the  walls  of  a  dwelling  or  stable, 
striking  them  at  a  right  angle,  the  pressure  so  developed 
tends  to  force  air  through  any  openings  in  the  windward 
side  with  an  intensity  approximately  equal  to  .125 x  Ib. 
per  sq.  ft.  and  equal  to  .0242  inch  of  water,  the  precise 
value  varying  with  the  weight  of  a  cubic  foot  of  air 
at  the  time,  this  changing  with  the  temperature,  pres- 
sure and  composition.  This  amount  of  pressure  is  the- 
oretically capable  of  causing  a  flow  through  a  smooth, 

1 .005  X  5  X  5  =  .125  Ibs.  per  sq.  ft. 

2 .00096  X  5  X  5  =  .024  inch  water  pressure, 


48  Ventilation. 

straight  cylindrical  ventilating  shaft  or  chimney  one  square 
foot  in  cross-section  and  40  feet  high,  equal  to  some  36,000 
cubic  feet  per  hour. 

Then  too,  whenever  the  wind  blows  directly  across  the  top 
of  a  chimney,  ventilator  or  other  opening  it  tends  to  pro- 
duce a  suction  which  has  the  effect  of  reducing  the  pressure 
at  the  opening  and  of  causing  a  flow  outward  increasing 
with  the  reduction  of  pressure.  The  magnitude  of  such 
wind  action,  in  its  tendency  to  produce  a  flow  of  air  into 
and  out  of  spaces  needing  ventilation,  is  given  by  the  equa- 
tion, 

Pressure  or  Head  =  .00024Y8, 

where  V  is  the  velocity  of  the  wind  in  feet  per  second  and 
where  the  head  or  pressure  is  in  inches  of  water.  If  the 
velocity  of  the  air  is  taken  in  miles  per  hour  this  equation 
becomes 

Pressure  or  Head  =  .000518V2. 

These  equations  mean  that  if  the  wind  is  blowing  at  the 
rate  of  five  miles  per  hour  across  the  top  of  a  ventilating 
flue  or  chimney  there  would  be  developed  a  suctional  effect 
or  head  equal  to,  using  the  second  equation, 

.000518  X  5  X  5  ^  .01295  inch  water  pressure, 

and  this  is  capable  of  producing,  in  a  flue  40  feet  high  with 
a  cross-section  of  one  square  foot,  a  theoretical  flow  of  some 
26,000  cubic  feet  per  hour.  Such  theoretical  velocities  as 
these  cannot  be  realized  in  practice  because  the  resistances 
met  with  by  the  air  in  entering  buildings,  ventilating  shafts 
or  chimneys  vary  between  wide  limits;  moreover  if  provi- 
sion is  made  for  air  to  enter  through  thin  openings  in  walls, 
such  openings  are  never  fully  effective  because  of  the  inter- 
ference of  currents  entering  obliquely  around  the  margins, 
causing  a  contraction  of  the  air  stream  which  may  reduce 
the  theoretical  flow  to  about  65  per  cent.  The  manner  in 
which  the  wind  becomes  a  motive  power  in  ventilation  is 
indicated  in  Fig.  22. 


How  Wind  is  Effective  in  Ventilation. 


49 


The  wind  has  its  progress  arrested  by  the  building, 
thereby  compressing  the  air  and  forcing  a  portion  of  it  into 
the  building  through  any  openings,  as  at  A,  while  other 


«-     *-  i 


Fig.  22. — Manner  in  which  the  wind  becomes  effective  as  a  motive  power 
in  the  draft  of  chimneys  and  in  ventilation. 

portions  are  driven  upward  along  the  sides  past  B  and  over 
the  roof  across  the  top  of  the  ventilator  at  C,  and  other  por- 
tions still  flow  around  the  corners.  The  air  entering  the 
building  at  A  is  either  forced  upward  through  the  ventilat- 
ing flue  at  D  or  out  through  any  openings  which  may  be  in 
the  leeward  walls  of  the  room.  That  portion  forced  past  B 
along  the  roof,  across  the  top  of  the  "ventilator,  joins  with 
the  general  wind  current  of  that  level  and  tends  to  drive 
the  out-coming  air  from  the  flue  forward,  diminishing  the 
pressure  of  the  air  downward  into  the  flue,  thus  making  less 
resistance  for  the  air  in  the  room  below  to  be  overcome  in 
its  ascent.  The  air  flowing  over  the  roof  of  the  building  in- 
creases the  pressure  on  the  leeward  side  at  E,  out  from 
which  air  flows  on  both  sides,  that  flowing  toward  the  build- 


50  Ventilation. 

ing  rising  along  the  sides  or  entering  it  at  F,  as  indicated 
by  the  small  arrows.  Thus  two  sources  of  power  are 
brought  into  operation,  compelling  air  to  enter  the  room  at 
A  and  F  and  leave  it  at  D,  one  being  the  direct  wind  pres- 
sure exerted  at  A  and  F  and  the  other  the  suctional  effect 
developed  at  C.  The  flow  through  the  building,  resulting 
from  wind  pressure  and  wind  suction,  will  be  most  rapid 


Fig.  23.— Showing  improper  installation  of  ventilating  flues  just  above  the 
eaves.  In  such  cases  whenever  the  wind  is  from  the  opposite  direc- 
tion the  tendency  will  be  to  give  a  much  reduced  draft  or  even  reverse 
its  direction,  causing1  it  to  be  downward  into  the  stable. 

when  these  two  factors  can  be  made  to  act  in  the  same  direc- 
tion and  with  the  highest  efficiency.  This  will  be  the  case 
when  the  wind  is  permitted  to  reach  the  building  at  A  and  to 
pass  over  its  roof  at  C,  meeting  with  the  least  obstructions. 
The  table,  page  57,  indicates  that  the  flow  due  to  direct 
pressure  is  stronger  than  that  due  to  suction  under  like 
wind  velocities.  It  will  generally  be  true,  however,  that  the 
suctional  effect  of  the  wind  is  the  stronger  of  the  two  for 
the  reason  that  the  wind  velocity  at  the  top  of  the  ventilat- 
ing flue  will  nearly  always  be  materially  stronger  than  near 
the  ground.  The  fact  of  wind  velocity  increasing  with 


Defective  Outtake  Shelter.  51 

hight  above  the  ground  is  expressed  in  Fig.  22  by  the 
length  of  the  arrows,  these  being  aprpoximately  propor- 
tional to  the  wind  velocities  at  such  levels. 

It  will  be  clear  from  what  has  been  said  that  the  top  of  a 
chimney  or  a  ventilating  flue  should  rise  well  above  the 
ridge  of  the  roof,  where  the  wind  has  a  clear  sweep,  and  not 
end  just  above  the  eaves  as  is  the  case  illustrated  in  Fig.  23. 

So,  too,  it  must  be  clear  that  anything  which  checks  the 
velocity  of  the  wind  across  the  top  of  a  chimney  or  ventilat- 
ing flue,  or  which  resists  the  escape  of  air  from  them,  must 
reduce  the  power  of  the  wind  to  produce  draft.  Such  caps, 
therefore,  as  are  seen  in  Fig.  23  and  as  is  represented  on  a 
larger  scale  in  Fig.  24,  designed  to  keep  out  the  storm,  must 
necessarily  materially  reduce  the  draft  and  should  be 
avoided  wherever  possible  unless  forced  ventilation  has  been 
adopted  and  the  current  is  maintained  by  mechanical 
power. 


Fig.  24. — Shelter  for  ventilating  flue,  designed  for  high  efficiency  In  keep- 
ing out  rain  but  which  materially  reduces  the  draft  in  "natural 
ventilation." 

Many  forms  of  cowls  have  been  devised  to  prevent  down- 
draft  in  chimneys  and  ventilating  flues,  and  with  a  view  to 
utilizing  the  wind  to  better  advantage  in  producing  draft. 
It  will  seldom  happen,  however,  that  these  need  be  resorted 
to  in  the  ventilation  of  ordinary  farm  buildings  or  rural 
schoolhouses  or  churches.  One  of  the  mistakes  most  often 
made  in  installing  a  ventilation  system  in  barns  is  illus- 
trated in  Fig.  25,  where  a  one-story  barn  is  provided  with 


52  Ventilation. 

short  ventilating  flues  which,  because  they  are  short,  have  a 
low  efficiency  and  then  this  efficiency  is  still  further  reduced 
by  covering  the  outlet  with  closely  louvred  shelters  which 
materially  diminish  the  effect  of  the  wind  in  aiding  venti- 
lation. 


Fig.  25.— Low  ventilating  flues  having-  their  efficiency  much  reduced  by 
closely  louvred  shelters,  diminishing  the  effect  of  the  wind  in  pro- 
ducing draft. 

A  much  better  construction  for  the  ventilating  shaft  is 
represented  in  Fig.  26  where  the  flues  are  not  only  higher 
but  the  outlet  is  shielded  in  such  a  way  as  not  to  materially 
impede  the  movement  of  the  passing  wind  or  the  escape  of 
the  air  from  the  ventilating  flue. 

Any  condition  or  cause  which  changes  the  density  of  the 
air  in  a  dwelling  or  stable,  rendering  it  lighter  than  an 
equal  volume  outside,  tends  also  to  establish  and  maintain 
a  current  of  air  flowing  through  it.  The  effect  of  both  heat 
and  the  addition  of  moisture  to  the  air  of  a  room  is  to  ren- 
der it  relatively  lighter  than  the  air  outside  and  so  long  as  a 
difference  in  density  is  maintained  there  is  a  difference  in 
pressure  which  tends  to  compel  a  continuous  flow  of  air  into 
and  out  of  the  space. 

When   air  is  warmed  or  cooled  its  volume  changes 
for  each  degree  F.  rise  or  fall  in  temperature.     Imagine  a 


Good  Termination  of  Outtake  Flue.  53 

room  containing  491  cubic  feet,  one  very  nearly  8  by  8  by  8 
feet.  If  the  air  in  this  room  has  its  temperature  raised  one 
degree  F.  the  expansion  so  caused  will  force  out  just  one  cu- 
bic foot  of  this  air  and  so,  if  the  temperature  is  raised  100 
degrees,  there  will  be  forced  out  of  such  a  room  100  cubic 
feet  and  the  air.  remaining  will  weigh  about  8  pounds  less 
than  an  equal  volume  outside.  This  being  the  case  there 
must  result  a  pressure  inward  tending  to  force  air  into  the 


Fig.  26.— Ventilating  flues  rising'  high  above  the  roof  and  with  outlet 
sheltered  so  as  to  permit  free  wind  movement  and  easy  escape  of  air 
from  the  flues. 

room,  a  pressure  equal  to  about  .08  pound  for  each  degree 
difference  in  temperature,  and  hence  8  pounds  where  the 
difference  is  100°  F.  Referring  now  to  Fig.  27,  which  rep- 
resents a  room  of  491  cubic  feet  capacity,  suppose  there  is 
an  opening  of  one  square  foot  area  in  the  floor  at  A  and  an 
equal  similar  opening  in  the  ceiling  at  B.  If  the  air  in  this 
room  is  maintained  at  70°  when  the  outside  air  is  30°  below 
zero  its  weight  will  be  8  pounds  less  than  that  of  an  equal 
volume  outside.  This  being  true  the  pressure  into  the  room 
at  the  floor  and  on  sides  and  ceiling  must  be  8  pounds 
greater  than  that  exerted  outward  by  the  inside  air ;  and 
since  the  floor  has  an  area  of  nearly 

8X8  =  (54  sq.   ft. 


54 


Ventilation. 


the  pressure  tending  to  force  air  into  the  room  at  the  floor 
opening  and  out  at  the  ceiling  must  be  one  sixty-fourth  of  8- 


Fig.  27. — Difference  in,  temperature  as  a  motive  power  in  ventilation. 

pounds,  or  .  125  Ib.  per  square  foot.  This  too  is  the  differ- 
ence in  weight  between  a  column  of  air  one  square  foot  in 
section  the  hight  of  the  room  and  an  equal  column  outside. 
So  long,  therefore,  as  such  a  difference  in  temperature  is 
maintained  air  must  tend  to  enter  at  the  floor  and  flow  out 
at  the  ceiling  at  the  rate  which  a  pressure  of  .  125  pound 


Difference  of  Temperature  a  Motive  Power.          55 

per  square  foot  is  capable  of  maintaining,  which  theoret- 
ically is  more  than  25,000  cubic  feet  per  hour. 

The  magnitude  of  the  temperatue  effect  in  producing 
draft  is  given  by  the  equation. 

Cu.  ft.  per  hour  =  60  X  CO  X  8  ,  ,/ZlZ*  H 
where 

60  X  60  is  number  of  seconds  per  hour; 

8  is  \  2g,  and  g  is  the  increment  of  gravity.  '.'*•>.  H\: 

T  is  temperature  of  the  air  inside; 

t  is  temperature  of  the  air  outside; 
«        II  is  height  of  room,  chimney  or  ventilator: 

.ji,  is  the  expansion  of  air  for  1°  F. 

Suppose  a  ventilation  flue  one  square  foot  in  section  40 
feet  high,  and  the  air  in  it  maintained  at  a  temperature  20° 
above  the  air  outside.  In  such  a  case  the  theoretical  flow 
through  the  flue  would  be  18,381  cu.  ft.  per  hour.1 

This  is  the  theoretical  rate  of  flow,  no  account  being  taken 
of  friction  or  other  forms  of  resistance.  The  actual  flow 
which  would  be  associated  with  such  a  difference  in  pres- 
sure might  be  fully  50  per  cent  less  than  this. 

The  effect  of  temperature  differences  in  producing  draft 
increases  with- the  hight  of  the  chimney,  ventilating  flue, 
and  with  that  of  the  room  or  stable.  It  is  because  of  the 
greater  leakage  of  warm  air  from  rooms  and  stables  with 
high  ceilings  that  it  is  more  difficult  to  keep  them  warm. 
This  will  be  readily  seen  from  a  consideration  of  the  prob- 
lem presented  in  connection  with  Fig.  27,  considering  the 
room  to  have  a  hight  of  16  instead"  of  8  feet.  Such  a  room 
would  contain  twice  the  volume  of  air  and  hence,  with  the 
same  increase  in  temperature,  the  expansion  would  cause 
an  escape  of  16  instead  of  8  cubic  feet  of  air.  The  air  of 
the  room  would  then  be  lighter  than  an  equal  volume  of 
that  outside  by  the  weight  of  16  instead  of  8  cubic  feet,  and 
hence  there  would  be  double  the  pressure  forcing  the  air 
to  enter  and  leave  the  room.  Computing  the  theoretical 


60  X  60  X  8  -,  /—  X  40  =  18381  cu.  ft.  per  hour. 
/     491 


56 


Ventilation. 


change  of  air  in  the  two  rooms  we  shall  have  for  the  one 
with  the  8-foot  ceiling  36,760  cu.  ft.  per  hour,1  and  for  the 
room  with  a  16-foot  ceiling  the  rate  of  air  change  would 
be  51,889  cu.  ft.  per  hour.21  If  the  two  rooms  under 
consideration  were  not  provided  with  special  openings 
for  the1  entrance  and  escape  of  air,  -as  represented  in 
Fig.  27,  and  the  air  was  required  to  enter  entirely 
through  leaks  in  the  walls,  approximately  the  same  rela- 
tive changes  of  air  would  take  place  and  it  is  clear  that 
it  is  much  more  economical,  both  in  cost  of  construction  and 
in  that  of  maintaining  proper  temperature  to  place  the  ceil- 
ings of  dwellings  and  stables  only  so  high  as  is  needful  to 
secure  convenience  and  sanitary  conditions;  aiming  to  se- 
cure the  necessary  rate  of  change  of  air  through  definite 
provisions  in  the  way  of  ventilation.  It  is  clearly  much 
cheaper  to  construct  a  tall  ventilating  flue  for  securing  the 
necessary  increase  in  the  rate  of  air  change,  than  it  is  to 
make  the  walls  of  rooms  and  stables  higher. 

In  the  table  which  follows  there  are  given  the  theoretical 
rates  of  flow  of  air  through  ventilating  flues  of  different 
hights  and  under  several  differences  of  temperature  main- 
tained inside  and  outside  the  flues. 

Computed  theoretical  flow  of  air  through  straight  ventilating  flues  one 
square  foot  in  cross-section,  of  different  lengths  and  under  8  tempera- 
ture differences.  The  observed  flows  are  likely  to  be  near  50  per  cent 
below  these  values . 


Difference 
in  temp. 
T-t. 

HEIGHT  OF  VENTILATING  FLUE,  H. 

20  ft. 

30  ft. 

40  ft. 

50  ft. 

60  ft. 

1°    

5,828 
18,409 
26,064 
31,922 
36,902 
41,211 
45.  144 
48,  761 

Flow, 

7,138 
22,572 
31.775 
39.096 
45,144 
50.  472 
55,291 
59,920 

cubic  feet  pei 

8,242 
26,064 
36,680 
45,  144 
52,  128 
58,214 
63.  843 
68,958 

-  hour. 

9,215 
29.  114 
41.211 
50.472 
58,214 
65.  159 
71.378 
77,098 

10,  095 
31,922 
45,144 
55,  291 
63,843 
71,378 
78,  192 
84,457 

10° 

20°       

30° 

40°        

50° 

60°          

70° 

/100 


1 60  X  60  X  8  -i  /  ~~  X  8  =  36760  cu.  ft.  per  hour, 

2  60  X  60  X  8   ,  /  ~  X  16  =  51889  cu-  ft-  Per  hour- 
§/       491 


Capacity  of  Outtake  Flues, 


57 


The  relation  between  wind  velocities  and  the  pressures 
due  to  impact  and  to  suctional  effect  are  given  in  the  next 
table,  together  with  the  flow  of  air  computed,  using  the 
formula  on  page  55,  where  the  wind  pressures  in  the  third 
and  sixth  columns  have  their  temperature  difference  equiva- 
lents computed  and  given  in  the  fourth  and  seventh  col- 
umns, these  being  used  with  the  formula  named. 


rw/yy  '//*'/  f/n-iin-finif  jtmr  ,,f  ,///•  f/ir<ti/t//i  a  jli/e  one  square  foot  in  cross- 
section  »/«t  4»  f«t  /"//.'/.  '/'/*-  /"  tin-  <tir«-f  impact  and  Auction  effect  of 
,it  i/ijf,  /•>,//  velocities. 


VELOCITY  <>i   \VIND. 

1  H  a  KCT'IMPACT. 

Sr  (  TIONAL  EFFECT. 

IVr 
hour, 
mike. 

Pwr 
teet 

Press-     Kquiva- 

U|-c.             Iclll   US 
llirhrs            T-t. 

>f  water.  (Irtnvrs. 

Plow 

IH'l-llOU!-. 

cu.  ft. 

Presa- 

HI'C. 

IIK-IH-, 
of  water. 

Equiva- 
lent a> 
T  t. 
degrees. 

Flow 
perhoup, 
cu.  ft. 

i 

1.47 
•'  ;>:; 

.IM.l 

.oo:{<i           :j.o; 

I1..'.*! 

.ni.-,:>           12.2ti 

.0242         i;u; 

.<>:;4'.t 
.('47.-. 
.IH^O            4H.«H5 

.0786          »«.IRI 

.(HHiit 
.1172            1'2.7:» 

.1  :;;•:>       no.  38 
.n;:;s        i  -.".»..  -,4 

.1!H«           l.Vl.:>4 

i7_'.i;-2 

7.'2ttl 
14.402 
21,603 

43,205 

57,601 
64,808 
72,009 
79,201 
86,411 
93,612 
100.813 
108,014 

.0005 

.0021 

.0047 
.INK; 
.0130 
.0187 
.o-j:»4 
.0832 
.0420 
.0518 
.0627 
.0746 

.1015 
.1166 

.41 
1.64 
3.69 

6.56 

10.24 
14.75 

20.08 
86.23 

:;:;.!  ;' 
40.98 

4i».:><> 
59.01 
«;«.'.  2:. 
80.32 
92.20 

5,272 
10,545 
15.817 
21.089 

2.;.  :w2 

31,634 
36,906 

42,178 
47,451 
52,723 
:,7.i".>:, 
63^268 
88,540 
715.  M  2 
79.085 

2 

4.40 
;  :;:; 

4  
5 

6  
7  

1  1  .  7:5 
13.20 
14.157 
16.13 
17.60 
1907 
20.53 
22iOfl 

8  
9  

10 

11  
12 

13 

14  

15  

If  the  flow  of  air  through  a  ventilating  flue  40  feet  high 
and  one  square  foot  in  cross-section,  as  given  in  the  two 
tables,  is  compared  it  will  be  seen  that  differences  of  temper- 
ature inside  and  outside  the  flue  ranging  from  one  degree 
to  sixty  degrees  F.  are  associated  with  computed  air  move- 
ments increasing  from  some  8,000  cubic  feet  with  a  differ- 
ence of  one  degree  P.  to  63,000  cubic  feet  per  hour  when  the 
difference  in  temperature  is  60°  F. ;  while  wind  velocities 
ranging  from  one  mile  to  nine  miles  per  hour,  acting  by 
direct  impact,  and  of  two  miles  to  twelve  miles  per  hour 
acting  by  suction,  give  approximately  equal  rates  of  flow. 
If  the  actual  velocities  were  one-half  these  computed 
amounts  the  slowest  rate  of  movement  would  a  little  more 


58  Ventilation. 

than  meet  the  needs  of  one  cow  while  the  most  rapid  move- 
ment would  permit  a  flue  one  square  foot  in  cross-section  to 
supply  nine  cows  at  the  rate  designated  on  page  41,  3,542 
cubic  feet  per  hour.  Such  a  rate  of  movement,  too,  through 
a  flue  one-fourth  of  a  square  foot  in  cross-section  would,  at 
one  half  the  slowest  rate,  supply  air  to  2  persons,  and,  at 
one-half  the  fastest  rate,  to  15  persons. 

The  wind  velocities  which  are  effective  in  producing  draft 
in  dwellings  and  stables  probably  do  not  have  a  yearly 
average  in  most  parts  of  the  United  States  greater  than 
four  to  six  miles  per  hour.  Taking  the  average  flow  due  to 
impact  equal  to  that  computed  for  the  four  mile  wind,  and 
that  due  to  suction  equal  to  the  computed  value  for  a  six 
mile  wind,  and  supposing  further  that  these  effects  are  fully 
additive,  the  mean  flow  due  to  wind  action  would  be  some 
60,000  cubic  feet  per  hour,  one-half  of  which  may  be  lost  in 
overcoming  unavoidable  resistance,  thus  leaving  30,000  cu- 
bic feet  per  hour  of  effective  flow,  which  is  sufficient  to  meet 
the  needs  of  more  than  eight  cows. 

The  temperature  difference  effective  in  ventilation,  not 
including  heated  chimneys,  is  perhaps  not  higher  on  the 
average  than  20°  F.  for  stables  nor  than  50°  for  dwellings, 
the  first  difference  being  capable  of  producing  a  flow  of 
36,000,  and  the  second  58,000,  cubic  feet  per  hour  in  a  40 
foot  flue  one  square  foot  in  section.  If  this  motive  power 
due  to  difference  in  temperature  be  added  to  that  derived 
from  wind  action  the  resulting  flow  would  be  some  96,000 
cubic  feet  of  air  per  hour  for  stables  and  120,000  for  dwell- 
ings, having  in  mind  theoretical  flows  and  a  ventilating  flue 
40  feet  high  and  one  square  foot  in  section.  Dividing  these 
results  by  two,  to  allow  for  loss  of  power  in  overcoming  re- 
sistance, the  remaining  motive  power  should  be  capable  of 
producing  a  flow  of  48,000  cubic  feet  per  hour  for  stables 
and  60,000  for  dwellings. 

In  his  "Air  Currents  and  the  Laws  of  Ventilation"  Shaw 
cites  experiments  wherein  the  observed  velocity  of  flow 
through  3-inch  metal  flues  about  25  feet  long  varied  from 
7,482  feet  per  hour,  when  the  wind  velocity  was  at  the  rate 


Observed  Air  Movement  Through  Outtakes.          59 

of  2.5  miles,  to  20,064  feet  when  the  velocity  of  the  wind 
was  15  miles  per  hour.  The  observed  flow  associated  with 
a  wind  of  4  miles  per  hour  in  these  experiments  was  8,448 
feet,  and  with  6  miles,  about  10,000  feet  per  hour.  At  the 
4-mile  rate  of  flow  a  square-foot  flue  would  meet  the  needs 
of  only  2£  adult  cows,  and  the  6-miles  rate,  not  quite  3 
cows.  In  these  trials  all  resistance  is  taken  into  account, 
the  flows  being  actual,  but  in  ordinary  ventilation  there 
would  be  added  the  temperature  effect  which  might  nearly 
double  the  efficiency. 

In  the  dairy  stable  of  the  Wisconsin  Experiment  Station, 
represented  in  Fig.  53,  page  112,  with  a  ventilating  flue1  ris- 
ing 60  feet  above  the  floor  and  with  the  main  shaft  40  in- 
ches in  diameter,  the  observed  flow  of  air  during  one  week 
was  as  follows: 

1st  day 205,377  linear  feet 

2nd  da v 205,800  linear  feet 

3rd  day 247,852  linear  feet 

4th  day 242,854  linear  feet 

5th  day 151,974  linear  feet 

6th  dav 132,822  linear  feet 

7th  day 153,720  linear  feet 

Here  is  an  observed  average  velocity  of  air  through  the 
main  ventilating  flue  of  7,978  feet  per  hour.  In  this  stable, 
however,  there  are  but  10  fresh-air  intakes,  each  with  an 
area  of  3  by  12  inches  and  each  of  these  is  covered  with  a 
register  face  which  reduces  their  efficiency  to  some  ex- 
tent so  that  the  aggregate  area  for  fresh  air  intakes  is  less 
than  2.5  square  feet.  The  walls  and  the  ceiling  of  the 
stable  are  covered  with  galvanized  iron  and  therefore  prac- 
tically air-tight  except  for  leakages  about  doors  and  win- 
dows. If  all  of  the  air  passing  through  the  ventilating  flue 
had  entered  the  stable  through  the  fresh-air  intakes  the 
velocity  through  them  must  have  exceeded  27,000  feet  per 
hour  which,  with  a  flue  one  square  foot  in  cross-section, 
would  supply  nearly  sufficient  air  for  8  cows. 

In  the  four  stables  of  H.  McK.  Twombly,  Fig.  26,  page  53, 
at  his  Florham  Park  farms,  New  Jersey,  in  July,  when  the 
cows  were  out  after  milking  at  night,  with  a  wind  move- 
ment outside  near  the  ground  less  than  50  feet  per  minute, 


60  Ventilation. 

the  rate  of  air  movement  was  found  to  be  as  recorded  be- 
low: 


Doors  and  win- 
dows open, 
per  hour. 

Doors  and  win- 
dows  closed, 
per  hour. 

Stable  No.  1... 

feet. 
11  040 

feet. 
8  690 

Stable  No   2 

7  740 

7  860 

Stable  No.  3..  .. 

8  340 

9  180 

Stable  No.  4  

8  640 

6  960 

Average  

8  940 

8  160 

The  ventilating  flues  in  these  stables  were  30  feet  high,  of 
galvanized  iron ;  4. 5,  3 . 5,  3  and  5 . 5  square  feet  respectively 
in  cross-section,  there  being  two  for  each  stable.  It  will  be 
observed  that  in  this  case  the  velocity  of  discharge  through 
the  ventilating  flues  averaged  somewhat  less  with  the  doors 
and  windows  closed  although  the  cross-section  of  the  fresh- 
air  intakes  aggregated  6,  4.3,  4.6  and  6  square  feet  for  the 
several  stables,  rather  more  than  the  cross-section  of  the 
ventilating  flues.  These  intake  flues,  however,  were  covered 
outside  and  in  with  register  faces  which  reduced  their 
effective  cross-section  probably  below  that  of  the  ventilators 
themselves.  Under  these  conditions  the  available  motive 
power  for  ventilation  was  probably  near  its  minimum  for 
the  air  near  the  earth's  surface  outside  was  almost  calm 
and  the  cattle  were  out  of  the  stable  so  that  the  only  avail- 
able heat  for  ventilation  was  the  little  that  may  have  been 
retained  by  the  walls  to  be  given  out  during  the  night. 
Notwithstanding  the  low  available  motive  power  the  wind 
movement  through  the  ventilation  flues  was  sufficiently 
rapid  so  that  a  current  a  square  foot  in  cross-section  was 
2 . 5  times  that  needed  for  one  cow. 

The  influence  of  moisture  as  a  motive  power  in  ventila- 
tion is  measured  by  the  effect  the  amount  transpired  or 
otherwise  added  to  the  air  has  in  making  that  within  the 
space  to  be  ventilated  lighter  per  cubic  foot  than  that  out- 
side. Take  the  case  of  air  outside  at  30°  and  weighing 
.08107  pound  per  cubic  foot  entering  a  stable,  becoming 
charged  with  moisture  to  the  extent  of  saturation  at  45° 


Moisture  as  a  Motive  Pmuer.  61 

and  having  its  temperature  raised  so  as  to  remain  at  50° 
when  in  the  ventilating  flue.  Air  so  changed  will  be  re- 
duced to  a  weight  of  .  07747  pound  per  cubic  foot,  thus  giv- 
ing rise  to  a  motive  power  in  a  ventilating  flue  40  feet  high 
equal  to  .027  inch  of  water,1  and  this  pressure  reduced 
to  its  equivalent  value  in  temperature  becomes  21.8°  F.2 
This  value,  21.814°  F.,  represents  the  combined  effect  of 
change  in  temperature  and  change  in  moisture  content  of 
the  air.  As- the  change  in  temperature  between  30°  and 
50°  is  20°  the  moisture  effect  must  have  a  temperature 
equivalent  of  1.8°  F.  This  temperature  equivalent,  acting 
as  a  motive  power,  or  aeromotive  force,  as  it  has  been 
called,  is  capable  of  producing  a  theoretical  flow  in  a  40 
foot  flue  of  11,073  cu.  ft.  per  hour.8  The  motive  power 
derived  from  moisture  added  to  the  air  of  a  venti- 
lated space  is  always  operative  in  assisting  ventilation 
and  its  magnitude  is  the  greater  the  more  completely 
the  air  is  saturated,  the  higher  is  its  temperature  and  the 
longer  the  ventilating  flue.  In  order,  therefore,  to  most 
fully  utilize  the  effect  of  moisture  as  a  motive  power  in  ven- 
tilation it  is  necessary  to  construct  warm  stables  and  to  so 
place  the  ventilator  that  its  walls  may  remain  as  warm  as 
practicable,  thus  avoiding  condensation  of  moisture  before 
leaving  the  flue. 

It  not  infrequently  occurs  that  the  motive  force  due  to 
wind  pressure  and  wind  suction  is  very  small  or  even  zero. 
We  have  found,  for  example,  that  at  Madison,  at  the  labor- 
atory very  near  the  shore  of  Lake  Mendota,  where  the  wind 
movement  was  measured  at  an  elevation  of  120  feet  above 
the  lake  and  82  feet  above  the  ground,  there  were  16  days 


1  (.081074  —  .077472)  X  40 

—  =  .027*  inch  water  pressure 

o.  2017 

.0277  X  491  X  5.2017  = 
40  X  .081074 


3  60  X  60  X  8  -.  / .       -  X  40  —  H073  cubic  feet  per  hour. 


62  Ventilation. 

m  January  when  during  the  night,  the  time  when  stables 
are  most  tightly  closed,  the  wind  velocity  did  not  average 
five  miles  per  hour  during  any  10  consecutive  hours  be- 
tween 7  p.  m.  and  7.  a.  m.  On  10  of  these  nights  the 
recorded  wind  movement  during  more  than  an  hour  was 
either  zero  or  less  than  one  mile.  At  such  times  as  these 
dependence  must  be  placed  upon  the  motive  power  derived 
from  rise  in  temperature  and  from  an  increase  in  the  moist- 
ure content  of  the  air  after  it  enters  the  stable.  It  is  im- 
portant therefore  to  know  what  the  minimum  motive  power 
from  temperature  and  from  moisture  changes  is  likely  to  be 
as  this  knowledge  is  fundamental  in  determining  the  proper 
dimensions  for  the  ventilating  system. 

As  dairy  stables  will  seldom  need  to  be  tightly  closed 
when  the  outside  temperature  is  above  30°  F.  and  as  at  this 
temperature  that  of  the  stable  is  likely  to  be  as  high  as  50° 
F.  it  may  be  assumed  that  the  minimum  motive  power  avail- 
able for  the  ventilation  of  such  stables  is  likely  to  be  not 
less  than  that  given  when  the  outside  air  enters,  saturated 
with  moisture,  at  30°  and  when  the  air  leaves  the  stable  at 
a  temperature  of  50°  and  containing  only  3.3  per  cent  of 
air  once  breathed.  Under  these  conditions  the  entering  air 
would  weigh  .0809  pounds  per  cubic  foot  and  before  enter- 
ing the  ventilating  shaft  would  be  reduced  by  changes  in 
temperature  and  composition  to  .0777  pound  per  cubic 
foot,  thus  giving  rise  to  a  motive  power  in  a  ventilating 
flue  40  feet  high  equal  to  .02461  inch  water  pressure, 
whose  equivalent,  expressed  in  difference  of  temperature,  is 
19.422°  F.  This  difference  in  temperature  is  capable  of 
giving  a  flow  of  36,227  cubic  feet  per  hour  through  a  ven- 
tilating shaft  one  square  foot  in  cross-section  and  40  feet 
high.  This  value  is  the  theoretical  flow.  Taking  the  effect- 
ive flow  equal  to  one-half  this  amount  we  shall  have  an 
hourly  supply  equal  to  18,113  cubic  feet  or  301  cubic  feet 
per  minute.  A  velocity  of  295  feet  per  minute  in  a  flue  2 
by  2  feet  in  cross-section  will  supply  20  cows  at  the  rate  of 
3,542  cubic  feet  per  hour  and  per  head,  and  this  is  the 
amount  needed,  as  previously  stated,  that  the  air  of  the 


Proper  Dimensions  of  Outtake  Flues.      •         63 

stable  shall  remain  96.7  per  cent  pure  or  shall  contain  at  no 
time  more  than  3,3  per  cent  of  air  once  breathed,  the  stand- 
ard we  have  assumed  as  possibly  permissible  for  dairy 
cows. 

In  the  case  of  barns  for  sheep,  piggeries  and  especially 
poultry  houses, 'where  lower  differences  of  temperature  are 
quite  certain  to  occur,  the  motive  power  must  necessarily 
be  less  when  the  wind  movement  is  small.  Besides,  in  these 
cases,  it  will  seldom  be  practicable  to  construct  as  long  ven- 
tilating flues  hence  relatively  larger  shafts  must  be  in- 
stalled or  other  equivalent  means  adopted  for  securing  the 
desired  change  of  air. 

To  make  clear  this  fact  let  us  assume  a  poultry  house  for 
the  accommodation  of  50  hens  each  needing  35  cubic  feei 
of  air  per  hour,  as  stated  on  page  41.  The  ventilating  flue 
must  therefore  provide  for  50  times  35  cubic  feet,  or  1,750 
per  hour.  Let  it  be  assumed  that  the  ventilator  has  a 
length  of  16  feet;  that  a  temperature  difference  of  only  4° 
is  maintained  in  it  when  the  outside  temperature  is  30°  F. ; 
and  that  the  rate  of  air  movement  is  to  be  such  as  to  main- 
tain a  purity  of  96.7  per  cent  with  a  moisture  saturation 
at  34°  of  90  per  cent.  With  the  outside  air  saturated  at 
30°  and  with  the  composition,  page  13,  its  weight  will  be 
.0809  pound  per  cubic  foot,  and  that  in  the  ventilating 
shaft,  at  34°,  90  per  cent  saturated  and  containing  3.3 
per  cent  of  air  once  breathed,  having  the  composition  of 
that  stated  on  page  14,  would  weigh  .08024  pound.  This 
gives  a  difference  of  pressure  between  the  air  in  the  16 
foot  shaft  and  that  of  an  equal  column  outside  of  .00066 
pound  per  square  foot.  Reducing  this  to  its  temperature 
difference  equivalent  it  becomes  .2504°  F.  Using  this 
value  to  compute  the  theoretical  flow  the  result  becomes 
2601.3  feet  per  hour,  which,  at  half  this  value,  leaves  an 
effective  flow  equal  to  1300.6  feet.  But  the  50  hens  re- 
quire 1,750  cubic  feet  of  air  per  hour.  The  size  of  the  ven- 
tilating flue  must  therefore  be 

1 750 

046  square  feet" 


64  „  Ventilation. 

This  area  is  given  by  a  rectangular  flue  14  inches  on  a 
side  and  by  a  circular  one  15.7  inches  in  diameter. 

MAINTENANCE    OF    TEMPERATURE    WITH    AMPLE    VENTILATION. 

It  may  appear  that  the  movement  of  such  large  volumes 
of  air  through  stables  and  dwellings  as  have  been  consid- 
ered needful  in  ventilation  is  incompatible  with  comfort 
and  economy  as  regards  warmth.  Let  us  see  what  are  the 
facts :  In  the  first  place  we  need  to  understand  that  nearly 
all  the  food  assimilated  or  utilized  in  the  body,  like  fuel 
burned  in  the  stove,  gives  rise  to  a  certain  amount  of  heat 
so  that  every  animal  and  person  is  in  a  sense  a  heat  gen- 
erating mechanism.  It  is  estimated  that  a  cow  produces 
and  gives  off  from  her  body  daily,  as  a  result  of  changes 
taking  place  in  the  food  she  eats  and  air  she  breathes,  an 
amount  of  heat  equal  to  76,133  British  thermal  units,  heat 
sufficient  to  raise  from  32°  F.  to  boiling  423 x  pounds  of 
water  and  it  is  enough  to  raise  the  temperature  of 
79,6032  cubic  feet  of  dry  air  from  0°  F.  to  50°  F. 
Thus  it  appears  that  the  heat  generated  by  one  cow  dur- 
ing 24  hours  is  sufficient  to  warm  approximately  79,600  cu- 
bic feet  of  air  through  50  degrees  F.  or  at  the  rate  of  3,316 
cubic  feet  per  hour.  This  amount  is  only  226  cubic  feet  of 
air  less  than  has  been  taken  as  possibly  sufficient  to  meet 
the  needs  in  dairy  stables.  It  should  be  understood  that 
during  the  winter  in  the  United  States  only  occasionally  is 
the  outside  air  at  a  temperature  as  low  as  0°  F.  Indeed 
the  mean  temperature  for  Wisconsin  for  January  is  nearly 
15°  and  a  rise  of  50  degrees  above  this  would  give  a  stable 
temperature  of  65°.  Taking  Doctor  Jordan's  estimate  of 
the  heat  given  off  by  a  cow  daily  equal  to  76,133  British 
units,  and  3,542  cubic  feet  of  air  per  hour  as  the  amount 
needful  for  each  cow,  and  supposing  that  the  whole  of  the 

i  75133 

=  422.96  pounds  of  water, 


180 
2  76133 


50  X  -237  X  .08071 


=  79G03  cubic  feet. 


Temperature  Maintenance  with  Ventilation.          65 

heat  so  generated  is  lost  through  the  air  passing  into  and 
out  of  the  stable,  this  heat  is  capable  of  warming  the  unit 
volume  of  air  through  47.55  degrees  F.  and,  on  this  as  a 
basis,  the  following  table  is  computed,  showing  approxi- 
mately the  temperature  of  stable  air  when  it  enters  at  dif* 
ferent  temperatures  at  the  rate  of  3,542  cubic  feet  per  hour 
and  per  cow. 

Approximate  f< ///j>r/'<tfi//-t  <>f  xtable  air  rctutifog  from  "i/////<t/ heat,  when 
entering  at  diffinut  t<  mperatures  at  the  rate  of  ./.>./.'  <-uhic  feet  per 
hour  and  per  <-<>ir, 

Temperature  of  Temperature  of 

outside  air.  inside  air. 

— 32°F.  15. 5Ti  F 

-10  37.56 

0  4;..V. 

10  :.:.:.:. 

15  1 5^.:,:, 
20 

25  72.55 

30  75.55 

Of  course  some  heat  is  lost  in  other  ways  than  through 
the  air  entering  and  leaving  the  stable  so  that  lower  tem- 
peratures than  those  in  the  table  must  be  expected  under 
the  conditions  stated  but,  as  the  average  winter  temperature 
in  the  United  States  is  materially  above  10°  it  is  clear  that 
good  ventilation  for  dairy  stables  is  possible  and  yet  permit 
reasonable  temperatures  to  be  maintained.  As  a  specific 
example  of  temperatures  actually  maintained  the  table 
which  follows  is  cited,  wherein  are  given  the  mean  daily 
temperature  of  the  dairy  stable  at  the  Wisconsin  Agricul- 
tural Experiment  Station,  during  two  weeks,  together  with 
the  outside  temperature,  the  total  air  movement  through 
the  stable  and  the  cubic  feet  of  air  per  cow  and  per  hour, 
as  observed  by  E.  L.  Jordan  in  a  thesis  study  relating  to 
the  influence  of  temperature  on  milk  production. 


66 


Ventilation. 


Mean  daily  temperatures  and^air  movement  through  a  dairy  stable 
containing  31  cows. 


DATE. 

AVERAGE  TEMPERATURE. 

FLOW  OF  AIR. 

Stable. 

Outside. 

Total  per 
hour. 

Per  cow  per 
hour. 

January  13 

56°  F. 
49 
50 
50 
47 
47 
54 
51 
50 
48 
47 
43 
44 
44 

13°  F. 
13 

20 
14 
13 
18 
28 
27 
25 
21 
—  2 
—18 
—16 
—11 

Cu.  ft. 

83,621 
86,965 
80,591 
83,522 
85,596 
89,768 
88,  435 
81,578 
105,  107 
92,317 
83,  479 
77,632 
81,882 
100.964 

Cu.  ft. 

2,697 
2,805 
2,600 
2,694 
2.761 
2,896 
2,853 
2,632 
3.  391 
2.978 
2,693 
2,508 
2,641 
3.257 

January  14  

January  15  . 

January  16..        .... 

January  17 

January  18.. 

January  19 

January  20  

January  21 

January  22.. 

January  23  

January  24.. 

January  25  

January  26.. 

This  table  shows  that  with  the  outside  temperature  rang- 
ing from  28°  to  -18°,  a  range  of  46  degrees,  the  stable  tem- 
perature varied  between  43°  and  56°,  a  range  of  but  13  de- 
grees, the  temperature  maintained  entirely  by  the  heat  of 
the  animals  and  this  with  a  measured  flow  through  the  ven- 
tilating shaft  at  no  time  less  than  2,500  cubic  feet  per  cow 
per  hour.  In  addition  to  this  flow  of  air  through  the  stable 
by  way  of  the  ventilator  there  was  undoubtedly  a  material 
leakage  through  the  windows  and  other  openings  which 
would  carry  the  air  supply  well  toward,  if  not  above,  3,542 
cubic  feet,  the  standard  assumed  as  possibly  adequate. 

The  amount  of  heat  required  for  warming  the  needed 
amount  of  air  for  good  ventilation  is  not  as  great  as  might 
be  expected  from  its  large  volume  for  the  reason  that  it  is 
very  light  and  because  its  specific  heat  is  very  low,  only 
.237  as  compared  with  1  for  water,  pound  for  pound. 
That  is,  it  takes  as  much  heat  to  raise  a  pound  of  water  one 
degree  as  it  does  to  raise  52  cubic  feet  of  air  through  the 
same  range  of  temperature.  With  hard  coal  at  $10.00  per 
ton  and  of  the  usual  fuel  value ;  with  the  outside  air  at  zero, 
to  be  raised  to  72°  inside,  and  supplying  10  persons  during 
24  hours  at  the  rate  of  537  cubic  feet  each  per  hour,  only 


Little  Extra  Heat  Needed  with  Good  Ventilation.    67 

11.26  pounds  of  coal  would  be  required  to  furnish  the 
needed  heat,  making  the  fuel  cost  but  5.63  cents  per  day 
for  thus  warming  the  necessary  amount  of  air  for  10  people. 
This  statement  must  be  understood  as  meaning  that  the  ex- 
tra amount  of  heat  in  house  warming  required  for  proper 
ventilation  is  but  very  little  above  that  required  where  only 
poor  ventilation  exists.  Stated  in  another  way,  to  main- 
tain the  proper  temperature  in  the  house  when  the  tempera- 
ture outside  is  zero,  without  any  ventilation  whatever,  re- 
quires a  certain  amount  of  fuel,  this  varying  with  the  type 
of  construction.  To  warm  the  necessary  amount  of  air  re- 
quired for  good  ventilation  during  24  hours  would  in  real- 
ity cost  less  than  5 . 63  cents  extra  for  10  persons  where  coal 
is  $10.00  per  ton,  because  a  part  of  this  heat  would  also  be 
available  for  maintaining  the  proper  temperature.  There 
is  therefore  little  ground  for  providing  insufficient  ventila- 
tion because  of  extra  expense  needed  for  fuel.  But  in  or- 
der that  the  maximum  air  movement  through  stables  may 
be  secured  without  the  aid  of  artificial  heat  or  mechanical 
appliances  and  that  good  ventilation  for  dwellings,  schools 
and  offices  may  be  had  without  unnecessary  cost  it  is  im- 
portant that,  so  far  as  possible,  the  exhaust  should  be  from 
the  coldest  part  of  the  room  which  will  be  usually  the  floor 
level. 

There  is  a  general  impression  that  because  respired  air, 
before  leaving  the  lungs  at  the  temperature  of  93°  to  97° 
F.  is  lighter  than  pure  air  at  room  and  stable*  temperatures 
it  must  rise  at  once  to  the  ceiling  and  that  for  this  reason 
ventilating  flues  should  exhaust  from  that  level  rather 
than  from  the  floor.  The  facts  are  that  respired  air  so  soon 
as  it  leaves  the  lungs  and  becomes  cooled  below  81°  is 
heavier  than  pure  air  at  the  same  temperature  because  of 
its  increased  content  of  carbon  dioxide,  the  moisture  it  is 
capable  of  holding  below  81°  not  being  sufficient  to  com- 
pensate for  the  increased  weight  due  to  the  carbon  dioxide 
added.  The  fact  will  be  made  clear  by  an  inspection  of 
the  next  table. 


68 


Ventilation. 


of  a  cubic  foot  of  pure  air  and  of  air  once  respired  by  man  at' 
different  temperatures. 


Pure  air 

Respired  air 

composition. 

composition. 

Temperature. 

O          20.61% 
CO2         .03% 

O        15.725 
CO8     4.350 

H20         .55% 

H9O    2.000 

N             78.81 

N        77.925 

70°... 

074316 

075293 

64  

Saturated 

60..     . 

075961 

076884 

50  

077605 

078544 

40. 

079049 

080205 

30  

080894 

081865 

29  8 

Saturated 

Here  it  is  seen  that  air  changed  in  composition  by  being 
respired  and  cooled  to  temperatures  between  70°  and  30° 

is  heavier  than  pure  air  at 
the  same  temperature.  As 
soon  as  respired  air  cools  be- 
low the  temperature  at  which 
it  becomes  saturated  by  its 
contained  moisture  a  portion 
of  this  must  be  condensed, 
leaving  it  heavier  because  of 
this  loss  of  moisture.  Thus, 
in  the  colume  of  respired  air, 
it  is  seen  that  it  become's  sat- 
urated at  64°  and'  when  it  is 
cooled  to  50° ,  instead  of 
really  having  the  weight 
there  stated,  on  the  basis  that 
it  could  contain  2  volume  per 
cent  of  moisture  at  that  tem- 
perature, its  actual  weight 
when  saturated  ie  .078765 
pound  per  cubic  foot,  which 
is  1.49  per  cent  heavier  than 
pure  air  at  the  same  temper- 
ature. 


Pig.  28. — Inverted  jar  being 
filled  with  respired  air. 


Density  of  Respired  Air. 


That  respired  air,  when  surrounded  by  pure  air,  either 
rises  very  slowly  or  tends  actually  to  fall  may  be  clearly 
demonstrated.  Let  the  Mason  jar  earlier  used  be  inverted, 
Fig.  28,  while  air  from  the  lungs  is  made  to  displace  that 
which  it  contains.  With  the  candle  already  lighted  let  the 
jar  be  at  once  lowered  over 
it,  Fig.  29.  The  flame  is  ex- 
tinguished as  it  was  in  an 
earlier  experiment  when  the 
candle'  was  lowered  into  the 
jar  filled  with  respired  air. 
But  if  the  trials  are  now  re- 
peated with  the  jar  both  in- 
verted and  placed  w  i  t  h 
mouth  up  it  will  be  found. 


Pig.  30.— Respired  air  soon 
drops  from  the  inverted 
jar  and  the  flame  is  not 
extinguished. 


Fig.  20.— Respired  air  in  in- 
verted jar  extinguishes  flame 
If  lowered  over  it  quickly. 


Fig.  30.  that  with  the  in- 
verted jar  materially  less  time 
is  required  for  the  respired 
air  to  become  so  changed  as 
to  permit  the  candle  to  burn 
in  it  than  is  the  case  when 
the  jar  stands  mouth  up.  This 
could  not  be  the  case  did  not 
the  rspired  air,  cooled  by  the 
walls  of  the  jar,  become- 
quickly  heavier  than  that 
outside. 


70 


Ventilation. 


These  experiments  and  statements  are  in  apparent  con- 
tradiction to  the  results  of  some  analyses  of  stable  air,  as 
in  the  case  in  the  dairy  stable  at  the  New  York  Agricul- 
tural Experiment  Station,  represented  in  Fig.  31,  where 
Dr.  Jordan  found,  as  an  average  of  analyses  made  on  two 
different  dates,  results  given  in  the  following  table : 

Composition  and  temperature  of  air  at  the  floor  and  ceiling  o/  the  dairy 
stable  at  the  New  York  Agricultural  E.vpa-lnn  nt  Station. 


Ventilator 
working. 

Ventilator 

closed. 

Temperature  of  air. 
At  ceiling1 

56  3°F 

64  4°F 

At  floor...  .                      .                   

50  0 

56.3 

Difference       .  .                                           

6  3 

8  1 

Composition,  volume  per  cent. 
HgO  at  ceiling1,  

.4815 

.525 

H2O  at  floor  

.7198 

.5465 

Difference  
CO2  at  ceiling  ..     .     . 

.2383 
5335 

.0215 
1.4 

CO     at  floor  

351 

1.0335 

Difference  

1825 

3665 

These  analyses  of  Doctor  Jordan  and  those  of  similar  im- 
port made  by  other  analysts  appear  to  the  writer  not 
in  necessary  contradiction  with  the  statements  made,  and 
that  they  should  not  be  thought  to  indicate  that  it  would 
be  better  for  ventiltors  to  exhaust  from  the  ceiling  rather 
than  from  the  floor  level.  In  the  case  of  the  New  York 
stable  it  appears  probable  that  the  circulation  of  the'  in: 
terior  air,  as  indicated  by  the  arrows  in  Fig.  31,  tends  to 
carry  the  respired  air  directly  to  the  ceiling  mechanically, 
notwithstanding  its  greater  weight,  thus  giving  the  ob- 
served distribution  of  products.  It  should  be  stated,  to 
make  the  situation  more  clear,  that  the  samples  of  air  ana- 
lysed were  taken  at  the  center  of  the  stable  between  the 
two  mangers  and  w^here  there  must  necessarily  be  a  ma- 
terial mechanical  effect  tending  to  maintain  an  upward 
current. 


Principles  of  Ventilation  Construction.  71 

But  whatever  may  be  the  truth  relative  to  the  distribu- 
tion of  products  of  respiration  in  dwellings  and  stables 
this  we  think,  should  hold  in  all  good  practice :  Maintain 
a  sufficient  air  movement  through  dwellings  and  stables  to 
insure  the  entire  air  content  in  every  case  being  sufficiently 
pure  for  thoroughly  healthful  conditions.  It  is  hardly  pos- 
sible to  make  the  air  movement  for  ventilation  too  large  so 
long  as  the  temperatures  are  right  and  there  can  be  no 
doubt 'that  the  largest  air  movement  with  proper  tempera- 
tures is  possible  only  when  ventilating  flues  exhaust  from 
near  the  floor  level.  It  is  important  to  remember,  too,'  in 
this  connection,  that  whether  waking  or  asleep,  whether 
standing,  sitting  or  lying,  the  supply  of  air  breathed  must 
be  drawn  from  near  the  floor  level  and  that  removing  all 
air  from  this  level  compels  the  return  of  an  equal  volume 
to  it. 

To  fully  utilize  the  heat  of  dwellings  and  stables  in 
economic  warming  and  in  securing  adequate  ventilation  it 
is  imperative  that  certain  principles  of  construction  and  of 
admitting  and  of  removing  air  should  be  adopted.  Speak- 
ing here  from  the  standpoint  of  stables,  without  artificial 
heat  or  forced  ventilation,  each  animal  must  be  regarded  as 
a  heater  which  is  warming  the  air  of  the  compartment  in 
three  ways:  (1)  by  direct  contact  of  the  air  with  the 
body;  (2)  by  rapidly  breathing  large  volumes  of  .it  and 
raising  its  temperature  at  once  to  between  93°  and  97°  F. ; 
(3)  and  by  direct  radiation  of  heat  to  walls,  ceiling  and 
floor  which  in  turn  warm  the  air  by  contact.  Because  the 
warmed  air  is  thus  rendered  lighter  it  is  forced  at  once  to 
the  ceiling  where  it  tends  to  collect,  while  the  coldest  air, 
settling  toward  the  floor,  gives  rise  to  an  internal  system  of 
circulation  represented  by  the  arrows  in  Fig.  31.  It  will  be 
seen  from  this  illustration  that  the  circulation  of  the  stable 
air  is  maintained  by  the  continuous  action  of  three  motive 
forces;  (1)  the  waste  heat  of  the  occupants  which  becomes 
effective  through  its  expansion  of  the  air;  (2)  the  mechan- 
ical or  bellows-like  action  of  the  chests  of  the  cattle  and  (3) 
the  loss  of  heat  by  conduction  through  the  outer  walls.. 


72 


Ventilation. 


Keferring  to  the  figure  the  arrows  show  that  from  the  bodies 
of  the  cows  convection  currents  rise   directly  toward  the 


ED 

cu  . 

ED. 

eg 

CD 

H   - 

ED 

ED 

C3 

Q  , 

m. 

m 

c§ 

Fig.  31. — Section  of  cattle  barn  at  New  York  Agricultural  Experiment 
Station.  I,  illustrating  convectional  system  of  air  currents  main- 
tained by  the  animals  and  the  cooling  of  the  outer  walls.  II,  side 
elevation  of  stable  viewed  from  inside,  showing  AA,  floor  entrance  to 
ventilating  flues;  BB,  ceiling  openings  to  ventilating  flues;  GGG, 
ceiling  openings  to  fresh  air  ducts;  WWWWWW,  windows,  and  DD, 
doors.  Ill,  side  elevation  of  stable  viewed  from  outside  showing 
GGG,  openings  to  fresh  air  ducts. 

ceiling ;  that  with  the  cows  facing  each  other  the  bellows- 
like  action  of  each  row  forces,  the  air  currents  so  formed  to 
meet  in  the  center  and  the  air  must  rise  and  then  flow  out- 
ward along  the  ceiHng  in  both  directions,  finally  descend- 
ing along  the  outer  walls,  at  the  same  time  mixing  with  the 
incoming  fresh  air  entering  at  the  several  intakes  GGG 
shown  in  the  side  elevations  II  and  III.  During  cold 
weather  and  especially  at  the  windows,  unless  they  are 
double,  and  all  along  the  walls  if  not  of  wood  or  hollow 
masonry,  so  as  to  be  poor  conductors  of  heat,  the  air  will 
be  cooled,  thus  rendering  it  heavier,  causing  descending 
currents  which  must  flow  along  the  floor,  maintaining  a 
more  or  less  strongly  marked  system  of  air  circulation 
within  the  stable,  which  tends  continuously  to  mix  the  re- 
spired air  with  that  entering  from  without. 


Principles   of   Ventilation   Construction.  »73 

From  this  tendency  to  the  formation  of  a  continuous  cir- 
culation of  air  within  the  room  to  be  ventilated  it  is  clear 
that  it  must  be  extremely  important  that  both  ceiling  and 
walls  should  be  air-tight  and  warm  in  construction.  With 
ceiling  and  walls  tight  and  poor  conductors  of  heat  and 
with  no  opportunity  for  air  to  enter  except  where  special 
provision  is  made,  near  the  ceiling  at  GGG  inside,  II,  Fig. 
31,  or  for  it  to  escape  except  at  the?  floor  level,  only  the 
coldest  air  is  permitted  to  leave  the  stable,  while  at  the 
same  time  the  fresh  air  must  be  mingled  with  the  warmest 
air  of  the  stable,  thus  having  its  temperature  raised  before 
reaching  the  animals.  Where  such  conditions  of  construc- 
tion are  secured  the  whole  ceiling  and  upper  walls  become 
a  continuous  radiator  of  heat,  sending  back  to  the  animals 
and  to  the  floor,  where  it  is  most  needed,  the  heat  which 
has  escaped  from  them.  By  admitting  the  fresh  air  from 
low  down  outside  and  at  the  ceiling  inside,  as  represented 
in  Fig.  32,  this  air  entering  from  all  sides  as  shown  by  the 
large  arrows  in  Fig.  33,  the  cold  incoming  air  is  thus  widely 
and  generally  mixed  with  the  warmest  air  of  the  stable, 
thus  having  its  temperature  raised  before  being  brought  to 
the  animals ;  while  with  the  ventilating  flues  opening  at  A, 
Figs.  31  and  32,  near  the  floor  level,  this  arrangement  not 
only  compels  the  coldest  air  to  be  removed  but  it  forces  a 
return  of  the  warmest  air  in  the  stable,  mixed  with  the 
fresh  air  from  outside,  and  thus  partly  warmed,  to  the  floor 
level  where  it  is  needed  both  for  warmth  and  for  respira- 
tion. 

So,  too,  in  the  ventilation  of  dwellings,  offices  and'  school- 
houses,  as  represented  in  Figs.  44  and  48,  by  admitting 
the  fresh  supply  of  air  at  the  ceiling,  where  the  highest 
temperature  exists,  not  only  is  the  heat  being  lost  by  up- 
drafts  through  leaks  utilized  to  warm  the  incoming  air, 
but  all  drafts  are  avoided  near  the  floor  level,  thus  making 
it  possible  to  have  maintained  the  maximum  air  movement 
through  the  rooms  without  danger  or  discomfort. 


74 


Ventilation. 


Referring  further  to  the  method  of  admitting  fresh  air 
to  stables,  illustrated  in  Fig.  31  and  32,  it  should  be  un- 
derstood that  the  position  of  the  outside  openings  for  the 
entrance  of  air  to  the  fresh  air  ducts,  placed  at  some  dis- 
tance below  that  admitting  the  air  to  the  stable,  is  funda- 
mentally important  for  the  reason  that  only  in  this  way 
can  the  escape  of  the  warmest  air  of  the  stable  through 


Pig.  32. — Section  of  dairy  stable  showing  the  action  of  the  wind  at  DD, 
forcing  air  into  the  stable  by  direct  pressure  at  BB  and  out  of  it  by 
suction  at  the  top  of  the  ventilating  shaft  AA.  At  C  is  a  ceiling 
register  in  the  ventilating  shaft  to  be  opened  only  when  the  stable  is 
too  warm  or  when  the  draft  is  too  feeble. 


such  openings  on  the  leeward  side  be  prevented.  Without 
some  such  provision  as  this  the  case  would  be  like  lowering 
the  windows  at  the  top  on  opposite  sides  of  stable  or  room, 
which  always  results  in  fresh  air  entering  on  the  windward 
side  and  warm  air  escaping  on  the  other.  With  the  ar- 
rangement adopted,  as  shown  in  the  illustrations,  only  a 
strong  wind  pressure  can  result  in  forcing  the  warm  air  ta 
descend  and  escape  through  intakes  on  the  leeward  side. 


Principles  of  Ventilation  Construction. 


75 


The  ventilation  of  offices  which  is  so  often  attempted  by 
raising  a  window  at  the  bottom  and  inserting  under  it  a 
screen  carrying  a  pair  of  short  Tobin  tubes,  like  up-turned 
pipe  elbows,  while  better  than  no  attempt,  can  seldom  give 
adequate  ventilation  where  steam  or  hot  water  is  used  for 
warming  for  the  reason  that  here  provision  only  is  made 
for  air  to  enter  and  this  can  take  place  no  faster  than 


Fig.  33. — Floor  plan  of  dairy  stable,  Fig.  32,  showing  fresh  air  intakes 
on  all  sides  at  the  large  arrows  crossing  the  walls;  two  ventilating 
flues  are  AA  and  the  air  approaching  them  along  the  floor  level  indi- 
cated by  the  small  arrows. 

opportunity  for  escape  exists.  The  opening  of  the  door 
into  a  hallway  or  of  the  transom  above  it  usually  has  only 
the  effect  of  making  the  box  to  be  ventilated  larger;  and 
the  result  usually  is,  with  such  makeshifts,  that,  on  windy 
days  during  cold  weather,  such  window  openings  are 
closed  to  save1  heat  and  during  still  weather  there  is  little 
motive  power  to  force  an.  air  movement  if  they  are  opened 
and  hence  much  of  the  time  very  inadequate  ventilation 
must  obtain. 


PRACTICE  OF  VENTILATION. 


In  coming  to  the  practice  of  ventilation  in  cold  climates 
the  problem  is  reduced  to  its  lowest  terms  when  it  is  stated 
that  the  desired  results  can  be  ideally  secured  only  when 
the  construction  of  the  building  to  be  ventilated  is  such 
that  no  air  can  enter  or  leave  it  except  at  appointed  places, 
and  when  all  heat  is  lost  through  the  outgoing  air  and 
-none,  or  as  little  as  possible,  through  the  walls.  While  it 
is  not  practicable  to  construct  enclosures  whose  walls  are 
either  air-tight  or  perfect  non-conductors  of  heat  it  is 
nevertheless  of  the  highest  importance,  as  leading  to  correct 
practice,  that  right  ideals  be  held  and  that  they  effectively 
direct  construction.  When  nearly  all  air  enters  and  leaves 
the  space  to  be  ventilated  at  the  appointed  places  and  when 
most  of  the  heat  is  borne  away  during  cold  weather  by  the 
air  leaving  the  room  or  stable  there  is  secured  the  largest 
practicable  rate  of  change  and  the  most  thorough  ventila- 
tion, which  is  the  object  sought.  Life  under  these  condi- 
tions may  live  to  its  fullest  capacity,  rather  than  survive 
by  the  narrowest  margin. 

BEST  ROOM  AND  STABLE  TEMPERATURE. 

The  fires  of  life,  kept  alight  through  all  the  organs  of  the 
body  by  the  incessant  fanning  of  the  lungs  and  the  tireless 
pumping  of  the  heart,  can  only  be  maintained  between  very 
narrow  ranges  of  temperature.  With  ourselves  and  with 
all  our  domestic  animals  the  temperature  within  the  body 
lies  close  to  100°  F.  If  the  general  active  tissue  tempera- 
ture falls  but  a  few  degrees  below  this  life  activities  must 


Best  Room  and  Stable  Temperature.  77 

cease;  within  the  healthful  but  narrow  range  chemical 
changes  go  forward  along  normal  lines  and  at  the'  normal 
rate ;  at  but  a  few  degrees  above  this  temperature  reactions 
occur  which  seriously  interfere  with  body  functions,  mak- 
ing them  abnormal  or  causing  them  to  cease. 

Since  most  of  the  activities  within  the  normal  body  re- 
sult in  the  generation  of  more  or  less  heat,  and  since  the  in- 
ternal temperatures  must  be  kept  near  100°  F.,  it  is  clear 
that  surrounding  temperatures  must  be  at  some  lower  de- 
gree than  that  of  the  body  in  order  that  a  rate  of  loss  of 
heat  equal  to  that  of  production  may  take  place.  In  our 
own  case  we  become  uncomfortable  when  the  surrounding 
temperature  rises  much  above  68°  to  70°  and  the  same  is 
true  of  our  domestic  animals.  Stables  and  dwellings  then, 
as  a  rule,  should  have  a  temperature  lower  rather  than 
higher  than  70°,  but  how  much  lower  than  this  is  best  must 
depend  upon  various  conditions.  Persons  engaged  in 
bodily  exercise,  and  animals  being  heavily  fed,  like  fatten- 
ing swine,  steers  or  sheep,  are  likely  to  do  better  in  some- 
what cooler  quarters,  (1)  because  the  greater  activity  as- 
sociated with  increased  assimilation  must  develop  more  heat 
and  this  must  be  removed  at  a  more  rapid  rate,  and,  (2) 
because  the  aim  in  feeding  such  animals  is  to  induce  them 
to  eat  as  much  food  as  can  be  economically  converted  into 
the  products  sought,  too  warm  quarters  tending  to  make 
the  need  and  desire  for  food  less. 

It  has  been  found  that  when  fasting  and  at  rest,  under  a 
temperature  of  90°,  a  man  consumed  some  1,465  cubic  inches 
of  oxygen  per  hour,  but  under  the  same  conditions  except 
that  the  surrounding  temperature  was  59°,  13  per  cent 
more  oxygen  was  consumed  and  a  like  increased  volume  of 
carbon  dioxide  thrown  off,  thus  showing  that  more  food 
must  be  eaten  to  compensate  for  the  increased  waste.  But 
in  eating  more  to  maintain  animal  heat  under  lower  tem- 
perature surroundings  it  is  probable  that  more  than  enough 
to  do  this  may  be  taken  and  hence  that  an  increase  in  the 
formation  of  useful  products  will  likewise  result.  When 
animals  are  simply  on  a  maintenance  ration  and  the  aim  is 


78  Ventilation. 

to  carry  them  with  the  least  amount  of  food  their  quarters 
should  then  be  as  warm  as  the  demands  of  health  will  per- 
mit. It  seems  likely  that  the  best  temperature  surround- 
ings for  animals  being  fed  high  will  be  found  to  lie  between 
45°  and  50°,  while  with  animals  on  a  maintenance  ration 
these  will  be  found  to  do  better  and  to  be  maintained  at  a 
lower  cost  under  temperatures  between  55°  and  65°.  With 
dairy  cows,  having  large  udders  only  scantily  clothed  with 
hair,  and  through  which  so  much  blood  must  flow,  it  may 
be  expected  that  a  temperature  perhaps  as  high  as  50°  to 
60°  will  be  found  best,  even  with  high  feeding,  although 
the  few  studies  known  to  the  writer,  which  have  been  made 
to  determine  this  matter,  have  resulted  in  inconclusive 
data. 

Because  full  comfort  and  complete  satisfaction;  ample 
and  appropriate  food  and  drink  properly  supplied;  and 
sufficient  unimpoverished  and  unpolluted  air  all  of  the 
time  are  the  indispensable  requirements  for  the  highest  ani- 
mal production,  and  because  we  have  never  known  an  ani- 
mal, however  well  fed,  to  voluntarily  take  to  the  open  field 
in  cold  weather  for  rest,  we  are  not  yet  convinced  that  a 
conveniently  arranged  and  sufficiently  warm  shelter  ade- 
quately ventilated  is  not  indispensable  to  the  highest  results 
from  winter  feeding  and  winter  maintenance. 

LIGHT  FOE  DWELLINGS  AND  STABLES. 

In  the  construction  of  every  dwelling  much  care  should 
be  taken  to  secure  an  ample  amount  of  light,  in  the  kitchen, 
in  the  dining  room  and  above  all  in  the  main  living  rooms. 
An  abundance  of  light  is  needed  not  only  to  facilitate 
work  but  to  make  the  best  of  intentions  more  certain  in  at- 
taining results.  Besides,  it  requires  an  effort  to  be  gloomy 
and  feel  ugly  in  the  face  of  a  hearty  laugh  and  a  bright 
sunny,  cheerful  room  has  much  the  same  effect  upon  those 
who  occupy  it.  Many  disease  germs  are  enfeebled  by  di- 
rect sunshine  or  are  destroyed  by  it.  Who  has  not  ob- 
served the  cat  deliberately  seek  out  the  sunny  spot  on  the 


Light  for  Dwellings  and  Stables.  79 

carpet  for  the  good  feeling  that  comes  with  it  and  lasts 
after  it.  A  sunny  window  is  equally  needed  and  enjoyed 
by  the  members  of  the  family  whose  duties  confine  them 
so  exclusively  to  the  house. 

The  number,  size  and  exposure  of  windows  best  suited  to 
the  requirements  of  dwellings  and  stables  is  not  well 
established  either  in  philosophy  or  in  practice.  It  should 
go  without  saying,  however,  that  sufficient  window  space 
must  be  provided  to  admit  ample  light  for  doing  all 
necessary  work  with  dispatch  and  efficiency  and  with- 
out an  undue  strain  upon  the  eyes.  How  far  beyond 
supplying  such  an  amount  of  light  it  is  best  to  go 
there  is  yet  much  room  for  difference  of  opinion,  owing 
to  the  present  state  of  knowledge,  as  to  the  efficiency  of 
light  of  different  intensities,  as  to  the  best  manner  of  ad- 
mitting light  to  dwellings  and  as  to  its  importance  in  dwell- 
ings and  stables  as  an  agent  in  sanitation.  So  much  is  being 
urged  upon  the  public  at  the  present  time,  especially  in  the 
matter  of  lighting  dairy  stables,  as  a  necessary  measure  of 
sanitation  that  it  becomes  a  matter  of  practical  moment  to 
have  the  problem  clearly  and  correctly  stated,  and  the  more 
so  because  efforts  to  secure  unsual  lighting  are  very  likely 
to  lead  to  deficient  ventilatioruin  dwellings  and  stables  in  all 
cold  climates. 

It  has  ever  been  and  it  must  always  remain  true  that  the 
life  resultants  of  every  type  are  necessarily  attained 
through  compromises.  Nature  has  never  been  an  extremist 
along  any  line  and  all  of  her  biologic  assets  have  accrued 
through  admitting  in  partial  potency  the  multitude  of  fac- 
tors always  operative  in  securing  the  result,  whether  that 
be  man,  stamped  with  the  highest  attainments,  or  the  dead- 
liest microbe  pitted  against  him.  And  so  we  are  here  con- 
fronted with  the  problem  how  much  of  light  is  most  whole- 
some in  the  dwelling,  and  how  much  light  may  be  admitted 
without  unduly  curtailing  other  essential  requirements. 

In  the  effort  to  put  into  practice  the  deductions  of  re- 
search and  the  recommendations  of  zealous  but  not  always 
sufficiently  informed  teachers  of  stable  sanitation  many  ser- 


80 


Ventilation. 


ious  mistakes  in  construction  are  being  made,  one  of  which 
is  illustrated  in  Fig.  34.  This  stable  is  far  from  the  best 
type  for  use  in  cold  climates.  Thus  constructed,  the  short, 
low  closely-capped  ventilators  tend  in  themselves  to  provide 
but  a  small  air  movement.  Then  with  the  row  of  hi^h  deck 


Fig.   34.— Showing  faulty  arrangement  of  windows  for  stables  in  cold 
climates,  the  effect  being  to  render  them  cold  and  damp. 

windows  there  is  provided  an  elevated  ceiling  space  into 
which  the  warmest  air  of  the  stable  immediately  rises,  car- 
rying with  it  the  heat  of  the  stable  beyond  where  it  can  be 
utilized  in  warming  the  incoming  fresh  air,  and  where,  be- 
cause of  great  hight  and  unavoidable  leaks,  much  of  this 
warmest  air  must  escape  through  the  roof,  tending  further- 
more to  even  carry  fresh  air  direct  from  the  intakes  along 
the  ceiling  and  out  through  the  ridge,  thus  diminishing  the 
lower  ventilation.  Such  a  stable,  unless  artificially  heated, 
must  either  be  very  cold  or  have  a  small  air  movement 
through  it.  In  either  case  the  air  must  be  damp  and  for 
this  reason  unsanitary.  The  side  windows  in  this  stable  are 
excellent,  both  in  dimensions  and  exposure,  but,  in  our 
judgment  six  or  seven,  instead  of  ten,  on  a  side,  would  have 
been  ample. 

If  it  shall  be  proven  imperative  to  admit  more  direct  and 
sky  light  into  stables  for  the  purpose  of  disinfection 
then  some  type  of  construction  embodying  the  principle 


Lighting  of  Stables. 


81 


represented  in  Fig.  35  must  be  adopted.  In  a  type  of  con- 
struction like  this,  with  double  windows  arranged  along  the 
slope  of  the  roof,  and  with  similar  windows  in  the  side  both 
direct  sunshine  and  reflected  light  from  the  sky  may  be  ad- 
mitted to  the  stable  from  all  zones  to  the  greatest  practi- 
cable extent  and  at  the  same  time  utilize  the  animal  heat 
in  keeping  the  stable  warm,  thus  permitting  a  maximum 
flow  of  air  through  the  stable  without  unduly  lowering  its 
temperature  or  rendering  it  damp. 


t 

Fig.  .&.— Cross-section  of  a  concrete  one-story  dairy  stable  designed  to 
admit  the  maximum  amount  of  direct  sunshine  and  of  diffused  light  from 
the  whole  sky,  leaving  it  at  the  same  time  warm  in  construction  so  as  to 
permit  the  maximum  air  movement  thus  combining  sunlight  and  desicca- 
tion to  the  greatest  practicable  extent  as  disinfecting  agents. 

'  It  does  not  appear  likely,  however,  that  such  extremes 
of  illumination  for  either  dwellings  or  for  stables  will  be 
found  materially  better  than  moderate  window  space  con- 
fined to  the  walls.  It  will  not  be  maintained  that,  even 
out  of  doors  where  direct  sunshine  is  at  a  maximum  both  in 
intensity  and  in  duration  and  where  the  full  hemisphere  of 
reflected  light  from  the  sky  is  added,  bringing  illumination 
from  every  side,  all  disease  germs  which  may  there  be 
present  are  destroyed  by  the  light.  Faced  by  this  general 
truth  relative  to  light  as  a  destroyer  of  disease  germs  it  be- 
comes clear  that  even  glass  houses  and  stables  cannot  be  ex- 
pected to  eradicate  germ  diseases.  In  dwellings  and  stables, 
far  more  than  out  of  doors,  shadows  cast  by  litter  and  fix- 
tures must  effectually  baffle  all  efforts  to  secure  anything 
more  than  partial  disinfection  through  the  action  of  light 
whether  coming  direct  from  the  sun  or  reflected  from  the 


82  Ventilation. 

sky.  The  greatest  safeguard  against  germ  and  all  other 
diseases  is  found  in  a  well  nourished  and  well  cared  fo> 
body  and  as  more  than  the  half  of  such  indispensable  nour- 
ishment must  be  pure  air,  lighting  beyond  a  fair  amount 
cannot  be  permitted  to  seriously  interfere  with  the  air  sup- 
ply of  stables  or  dwellings. 

Dr.  Weinzirl,  of  Washington  University,  whose  has 
made  recent  critical  studies  along  the  line  of  light  as  a 
destroyer  of  disease  germs  and  particularly  those  of  tuber- 
culosis, wrote,  under  date  of  Feb.  17,  1908,  as  follows: 

"In  reply  to  your  question  as  to  the  value  of  sunlight  in 
stable  disinfection  and  the  feasibility  of  this  method  I  will 
say  that  in  my  opinion  sunlight  is  of  little  value  and  prac- 
tically of  no  value  under  prevailing  conditions,  nor  do  I 
believe  that  it  can  be  made  valuable  by  merely  increasing 
the  amount  of  diffused  light  through  side  windows.  I  ex- 
posed tubercle  cultures  on  the  window  sill  on  north  window 
for  a  week  and  yet  about  one-half  of  them  grew.  As  to  the 
other  half  I  am  inclined  to  think  that  desiccation,  and  per- 
haps other  factors,  entered  to  kill  the  culture.  At  any  rate 
non-spore  bearing  bacteria  are  more  readily  killed  by  dry- 
ing than  is  generally  believed.  A  day  or  two  will  suffice  to 
kill  many  of  them." 

In  another  letter  Dr.  Weinzirl  qualifies  the  views  as 
above  expressed,  writing  under  date  of  Oct.  19,  after  the 
other  was  in  type.  He  says: 

"I  have  made  a  good  beginning  on  the  problem  of  im- 
portance of  diffuse  light  and  as  a  result  of  this  work  I 
have  to  revise  my  views  quite1  materially. 

The  shortest  time  in  which  diffuse  light  in  a  room  killed 
the  bacillus  of  tuberculosis  was  less  than  a  day  and  the  long- 
est time  was  less  than  a  week ;  generally,  three  or  four  days 
of  exposure  killed  the  organism. 

Some  pus-producing  bacteria  required  a  week's  time  to 
kill  them,  while  some  intestinal  bacteria  were  killed  in  a 
few  hours.  It  was  also  found  that  bacteria  are  killed  more 
quickly  in  a  moist  air  than  in  a  dry  one,  contrary  to  general 
belief. 


Sanitary  Effect  of  Light.  83 

The  diffuse  light  as  found  in  our  dwellings  is,  therefore, 
a  hygienic  factor  of  great  importance,  and  where  direct 
sunlight  is  not  available,  it  should  be  carefully  provided 
for." 

It  may  be  added  as  supplementary  to  Dr.  Weinzirl's  let- 
ter just  quoted  that  he  also  made  at  the  same  time  control 
exposures  in  the  dark  which  showed,  for  the  six  groups  of 
trials  made  between  March  3  and  July  2,  and  on  as  many 
dates,  that  no  growth  took  place  after  intervals  varying 
from  2  to  10  days,  the  exact  times  after  which  all  germs 
were  dead,  or  after  no  growth  was  observed,  being  10,  7,  8, 
9,  2,  and  5  days  respectively  while  the  corresponding  times 
for  the  diffuse  light  were  5,  3,  5,  6,  1,  and  4  days.  The 
averages  of  these  two  groups  of  intervals  stand  in  about  the 
ratio  of  7  to  4,  which  means  that  under  the  conditions  of 
exposure  adopted  and  the  method  of  testing  viability  the 
life  of  tuberculosis  germs  was  rather  less  than  4  days  in 
diffuse  room  light  and  that  in  the  dark  their  life  was  less 
than  7  days.  But  it  would  be  very  misleading  to  leave 
light  as  an  agent  of  disinfection  with  the  reader  thus 
stated.  It  should  be  understood  that  direct  sunshine  is  far 
more  potent  in  destroying  disease  germs  than  is  reflected 
light  and  that  that  from  the  noon  sun  is  stronger  than  the 
light  coming  from  it  earlier  or  later  in  the  day.  Most  im- 
portant of  all  to  remember,  for  the  direction  it  should  give 
to  practice,  is  the  fact  that  even  in  the  brightest  sunshine 
the  slightest  shadows  materially  cut  down  its  power  to  de- 
stroy germ  life,  so  that  under  the  hay  and  bedding  of  the 
stable  and  especially  in  the  dung,  where  germs  ma*y  abound, 
effectual  darkness  may  obtain  where  the  direct  sunlight  of 
noon  is  falling.  Here  is  the  kernel :  Utilize  to  the  fullest 
practicable  extent  every  available  agent  of  destruction,  but 
remember  that  in  every  infected  stable  and  home  although 
millions  of  germs  may  be  destroyed  multitudes  will  escape 
and  the  losses  will  be  made  good  from  the  springs  of  life. 
Remember,  too,  it  is  within  the  body,  where  effective  dark- 
ness always  prevails,  that  injury  is  done  if  it  is  powerless  to 
resist,  hence  no  amount  of  sunshine  can  compensate  for  the 


84  Ventilation. 

diminished  bodily  vigor  which  results  from  insufficient  ven- 
tilation, or  other  food  supply. 

It  is  important  to  understand  something  of  relative  in- 
tensities of  the  light  received  from  the  sky  from  different 
quarters  and  of  that  direct  from  the  sun  compared  with 
that  from  the  sky.  Dr.  C.  G.  Abbot  of  the  Smithsonian  In- 
stitution and  Director  of  the  Astro-physical  Observatory, 
has  determined  the  relative  intensities  of  sky  light  coming 
from  different  elevations  above  the  horizon  from  Mount 
Wilson  at  the  time  of  clear  sky  in  August  and  September 
with  results  given  in  the  table  below : 

Average  brightness  of  the  sky  at  diffa-riit  distances  above  the  horizon. 


Altitude. 
0°  to  10°  

Relative  ii 
460 

uteiisity. 
4.00 
1.82 
1.61 
1.31 
1.11 
1.06 
1.00 

10    to  20  

210 

20    to  30  

185 

30    to  40  .. 

150 

40    to  55  

198 

55    to  75  

122 

75    to  90  .  . 

115 

This  table  makes  it  appear  that  windows  taking  light 
from  near  the  horizon  may  receive  nearly  four  times  the 
amount  of  that  coming  from  directly  overhead  supposing 
the  windows  vertical  in  the  first  case  and  horizontal  in  the 
second  and  no  obstructions  whatever  in  either  instance. 
As  to  the  relative  intensities  of  sky  light  coming  from  the 
south,  east,  north  or  west  Dr.  Abbot  writes  as  follows  under 
date  of  Oct.  28,  1908 : 

' '  I  regret  that  our  observations  on  the  sky  have  not  been 
conducted  excepting  on  Mount  "Wilson,  and  that  they  are 
scanty  even  there,  so  that  my  replies  to  your  questions  can- 
not, I  fear,  be  very  satisfactory  to  you. 

I  feel  sure  that  most  light  will  be  received  from  the  sky 
if  the  stable  windows  face  south  (obstructions  of  course  be- 
ing absent).  East  and  west  will  be  nearly  alike  in  this  re- 
spect, but  in  most  sections  west  will  receive  more  than  east. 
North  is  least  favorable. 

Less  sky  light  will  be  received  at  high  altitudes  above  sea 
level  and  at  very  clear  localities  than  at  low  and  hazy  sta- 
tions. 

The  horizon  is  much  brighter  than  the  zenith  so  that 


Intensity  of  Sky  Light.  85 

where  trees  and  hills  do  not  obstruct  the  view  the  windows 
would  receive  most  light  I  suppose  if  they  were  horizontal 
rather  than  vertical  in  their  longer  dimensions.  I  incline 
to  think  that  horizontal  windows  adapted  to  receive  light 
from  the  horizon  to  30°  altitude  with  unobstructed  south- 
ern exposure  would  receive  as  much  as  four  times  the  light 
equally  large  vertical  windows  with  north  exposure  and 
adapted  to  receive  light  from  30°  to  90°  altitude  would 
admit.  But  this  is  not  a  computation  and  is  not  applicable 
to  all  latitudes  and  altitudes  above  sea  level,  but  is  only 
intended  as  a  probable  estimate  to  suit  average  conditions 
in  the  United  States.  In  winter  the  advantage  of  horizon- 
tal southern  windows  is  greater  than  in  summer. 

As  to  the  disinfecting  qualities  of  the  sky  light  at  dif- 
ferent zenith  distances  I  know  nothing.  It  seems  prob- 
able to  me,  however,  that  if  any  such  qualities  exist  in 
zenith  sky  light  they  would  be  found  in  at  least  equal  and 
probably  in  greater  total  amount  (not  percentage),  in  the 
horizon  sky  light. 

I  do  not  know  whether  the  disinfecting  properties  of 
light  are  cumulative  as  the  photographic  action  is,  or  far 
greater  if  the  light  is  very  intense  like  the  rise  of  temper- 
ature of  a  body  in  the  focus  of  a  lens.  If  the  former  is  the 
case  I  should  have  little  question  that  the  continued  action 
of  sky  light  would  be  preferable  to  the  brief  action  of  sun- 
light. The  whole  sky  at  sea  level  is  apt  to  contribute  nearly 
as  much  light  as  the  sun,  and  by  far  the  larger  proportion 
in  middle  northern  latitudes  .comes  from  the  southern  half 
of  the  sky. 

The  above  opinions  are  presupposing  a  generally  clear 
sky.  If  the  sky  is  most  of  the  time  cloudy,  southern  ex- 
posure would  still  be  preferable  but  the  horizon  would,  I 
think,  cease  to  be  the  best  part  of  the  sky." 

If  Dr.  Abbot's  views  thus  tentatively  expressed  shall  be 
found  correct  stables  and  dwellings  should  be  lighted  as 
far  as  practicable  from  the  south  for  the  reason  that  both 
direct  sunshine,  in  the  middle  north  latitudes  and  the  max- 
imum amount  of  sky  light  may  thus  be  obtained.  In  the 
eastern  part  of  the  United  States,  east  of  Kansas,  the  aver- 


86 


Ventilation. 


age  per  cent  of  sunshine,  computed  on  the  total  possible, 
is  near  56.  Taking  this  in  connection  with  the  fact  that 
generally  a  considerable  portion  of  the  horizon  to  an  alti- 
tude of  10°  is  obstructed  we  are  inclined  to  favor  windows 
with  their  long  dimension  up  and  down.  The  difference 
will  be  made  clear  from  a  study  of  Fig.  36,  where  it  is  seen 
that  the  point  A  on  the  floor  receives  sky  light  through  the 
window  E  from  between  20°  and  50°  above  the  horizon 
while  from  the  window  W,  having  half  the  vertical  height, 
light  comes  in  between  20°  and  35°.  If  the  lower  light  is 
most  intense  the  last  window  will  admit  the  most  sky  light, 
but  if  the  higher  light  is  best  then  the  former  window  is  to 
be  preferred,  from  the  standpoint  of  sky  light.  With  the 
high  window,  as  seen  at  C  and  B,  direct  sunshine  must 
sweep  a  materially  broader  floor  area  than  if  it  is  short. 


Fig.  36.— Influence  of  hight  of  windows  on  the  admission  and  distribu- 
tion of  light  in  a  building;  B,  C,  area  of  direct  sunshine;  heavy  arc  of 
circle  subtends  angle  of  diffused  light  falling  at  A. 

In  low  stables  with  wide  overhanging  eaves,  and  where 
windows  are  under  porches,  the  same  area  of  glass  admits 
very  materially  less  light,  as  is  evident  from  an  inspection 
of  Fig.  37.  The  overhanging  eaves  at  A,  it  will  be  seen, 
cut  out  half  the  direct  sunshine  and  at  the  same  time  ma- 
terially prevent  the  entrance  of  diffused  light  from  the  sky. 
From  the  other  side  of  the  building,  where  the  eave  does 
not  overhang  so  far,  both  the  quantity  of  direct  and  of  re- 


Efficiency  of  Windows. 


87 


fleeted  light  are  seen  to  be  materially  increased  over  that 
entering  the  opposite  window,  as  shown  by  the   length   of 


Fig.  37.— Effect  of  overhanging   eaves  and   porches   in  reducing  the  effi- 
ciency of  windows. 

the  direct  sunshine  areas  D  and  E  and  by  the  size  of  the 
angles  of  diffused  light  falling  at  the  point  C. 

It  should  be  remembered  too  that  where  the  walls  of  a 
building  are  thick  relatively  larger  windows  are  required 
to  secure  the  entrance  of  the  same  amount  of  light,  the  fact 
being  made  clear  by  a  study  of  Fig.  38.  The  window  at  P, 


h "-£%CP-" H 


Fig.  38.— Showing  the  effect  of  thickness    of  wall    In    reducing    the    effi- 
ciency of  windows. 

four  feet  high  in  a  wall  one  and  a  half  feet  thick,  has  its 
direct  sunshine  efficiency  reduced  nearly  one-fifth  by  the 
thickness  of  the  wall,  as  shown  by  the  area  marked  H, 


:88  Ventilation. 

' '  sunshine  cut  out, ' '  with  a  width  for  this  window  of  three 
feet,  as  shown  at  A,  and  with  a  thickness  of  wall  of  18  in- 
ches, the  angle  at  which  sky  light  may  enter  is  reduced 
from  180°  to  128°,  while  a  wall  of  half  this  thickness  re- 
duces the  angle  for  diffused  light  only  to  150°.  With 
larger  windows  for  the  same  thickness  of  wall  the  percent- 
age loss  of  efficiency  is  less.  In  the  case  of  direct  sunshine 
the  drawing  represents  the  smallest  possible  reduction  with 
the  sunlight  entering  at  the  angle  represented,  the  building 
T)eing  supposed  to  face  the  south  with  the  sun  at  noon. 
At  any  time  before  or  after  noon,  with  the  same  altitude  of 
the  sun,  a  still  greater  reduction  than  that  represented 
must  take  place. 

VENTILATION  OF   DWELLINGS. 

It  is  safe  to  say  that  before  the  close  of  another  hundred 
.years  a  very  large  proportion  of  the  dwellings  now  in  use 
will  have  been  entirely  rebuilt  or  extensively  remodeled 
and  that  it  is  now  none  too  early  to  begin  a  campaign  of 
education  which  shall  lead  to  the  rebuilding  or  remodelling 
of  those  dwellings  along  lines  which  will  make  them  thor- 
oughly sanitary,  convenient,  pleasant  and  capable  of  being 
economically  maintained  in  all  of  the  ways  which  can  con- 
tribute to  substantial  home  comfort  and  character  building. 

It  is  also  safe  to  say  that  at  least  two  more  generations 
will  be  compelled  to  grow  up  in  the  dwellings  now  in  use 
but  which  are  far  less  sanitary,  from  the  standpoint  of  ade- 
quate ventilation  than  were  those  of  the  grandparents  of 
the  children  now  sixty.  Then,  in  whatever  other  ways 
those  homes  may  have  been  deficient,  there  was  continually 
moving  through  them  an  abundance  of  undiluted  and  un- 
polluted air.  The  wide-open  throat  of  the  great  fireplace 
of  those  days,  which  never  could  be  closed,  was  everlast- 
ingly sucking  out  of  the  few  rooms  and  in  through  the 
chinks  in  the  wall,  great  volumes  of  air  such  as  few  people 
living  in  modern  dwellings  can  realize.  Today,  with  win- 
dows double;  with  walls  sheated  inside  and  out,  sided, 
plastered  and  papered,  on  retiring  we  close  everything 


Ventilation  of  Dwellings.  89 

tight,  even  to  the  heater  and  kitchen  range,  and  wake  the 
next  morning  from  troubled  slumber  hoping  that,  whatever 
else  may  not  have  been  for  the  best,  we  have  at  least  saved 
a  little  of  the  $9.50  per  ton  coal.  Clearly  if  the  two  gener- 
ations which  must  dwell  in  the  old  homes  can  be  led  and 
helped  to  better  conditions  of  living  in  them  great  present 
and  future  gain  will  result.  The  vast  throng  of  yictims 
annually  and  prematurely  wilting  and  fading  away  before 
the  dreaded  white  plague  meet  disaster,  not  so  much  be- 
cause of  the  great  numbers  and  wide-spread  distribution  of 
the  disease  germs,  as  because  of  the  terrible  prevalence  of 
such  living  conditions  for  cattle  and  people  alike  as  convert 
the  weak  among  them  into  hotbeds  for  the  breeding  of 
tuberculosis  germs.  Disease-germ-bearing  milk  is  only  one 
of  a  thousand  vehicles  by  which  these  germs  are  spread  and 
helped  to  gain  a  new  foothold.  If  we  shall  ever  succeed  in 
greatly  reducing  the  numbers  of  its  victims  it  must  be 
through  fortifjdng  the  individual,  rendering  him  capable 
of  resisting  the  development  of  the  disease  germs  even  if 
they  are  introduced  into  the  system,  and  this  must  come 
through  more  wholesome  conditions  and  habits  of  living. 

It.  cannot  be  too  forcibly  impressed  upon  the  manage- 
ment of  households  that  when  one's  duties  are  such  that 
much  of  the  time  is  spent  in  the  open  air,  or  that  one  is  out 
and  in  frequently,  the  consequences  that  follow  inadequate 
ventilation  are  likely  to  be  far  less  serious  than  upon  those 
confined  more  exclusively  to  the  house.  It  should  be  re- 
membered too  that  the  person  whose  system  has  just  been 
thoroughly  renovated  by  breathing  an  abundance  of  fresh 
air  is  less  sensitive  to,  except  for  the  moment,  and  can 
safely  endure,  degrees  of  air  pollution  which  may  be 
oppressive  and  dangerous  to  those  continually  confined  to 
inadequately  ventilated  rooms.  And  so  it  often  happens 
that  the  menfolk  of  the  farm  are  living  fairly  well,  while 
the  women  in  the  same  home  may  be  suffering  scvrcly. 
especially  during  the  winter,  for  lack  of  proper  ventilation. 
Thought  and  judgment,  therefore,  exercised  in  the  house  as 
well  as  in  the  barn,  is  necessary. 


90  Ventilation. 


Ventilation  of  Houses  Already  Built. 

When  the  heating  of  the  house  is  by  means  of  stoves 
placed  in  the  living  rooms  a  certain  amount  of  ventilation 
is  secured  through  the  direct  action  of  the  stove,  for  all  of 
the  air  which  enters  the  stove  and  leaves  the  room  through 
the  chimney  is  drawn  into  the  house,  through  chinks  in  the 
walls  where  no  special  provision  for  entrance  is  made,  and 
so  long  as  the  draft  of  the  stove  is  open  there  may  be  suffi- 
cient ventilation  for  the  time  but  so  soon  as  the  draft  is 
closed  and  air  ceases  to  escape  through  the  stove,  inade- 
quate ventilation  is  likely  to  result.  Suppose  it  is  in  the 
evening  and  five  of  the  family  are  gathered  about  the  table 
in  a  room  15  by  15,  with  a  9-foot  ceiling  and  that  they  are 
using  a  lamp  whose  power  to  vitiate  the  air  is  equal  to  that" 
of  10  candles  such  as  used  in  Fig.  13.  There  would  then 
be  a  consumption  of  air  in  the  room  equal  in  amount  to 
that  demanded  by  nine  or  ten  people.  We  have  found  the 
ordinary  student-lamp  to  burn  kerosene  at  the  rate  of  38.4 
grams  per  hour  and  this  demands  oxygen  equivalent  to 
more  than  six  people,  so  that  it  is  safe  to  say  that,  with  five 
people  and  such  a  lamp,  air  is  needed  for  the  equivalent'  of 
ten  people,  and  this  demands  an  air  movement,  to  maintain 
the  standard  of  purity  which  we  have  assumed  as  possibly 
permissible  for  dairy  stables,  equal  to  5,370  cubic  feet  per 
hour,  which  requires  the  room  to  be  emptied  of  all  its  air 
and  refilled  once  about  every  22.6  minutes.  It  will  be 
readily  seen  from  this  statement  of  fact  that  whenever  the 
room  becomes  a  little  too  warm,  so  that  the  drafts  in  the 
etove  are  all  closed,  such  a  room,  not  otherwise  ventilated, 
would  very  soon  become  unsanitary  from  the  standpoint  of 
pure  air.  Indeed,  with  no  interchange  of  air,  in  one  hour 
nearly  one-tenth  of  the  whole  air  of  the  room  would  have 
been  used  once,  and  in  once-breathed  air  we  have  seen  the 
candle  extinguished. 

Let  us  see  now  what  the  stove  can  do  for  us  in  the  way 
of  ventilation  when  the   drafts   are   open.     Suppose  the 


Combined  Heater  and  Ventilator.  91 

chimney  is  30  feet  high  and  the  air  in  the  chimney  is  main- 
tained at  a  temperature  50  degrees  above  that  of  the  air 
outside.  From 'the  table,  page  56,  the  theoretical  flow 
through  a  one-foot  square  chimney  30  feet  high  is  50,472 
cubic  feet  per  hour.  With  half  this  efficiency,  to  allow  for 
resistances  to  be  overcome,  and  taking  the  cross-section  of 
the  6-inch  stovepipe  through  which  the  air  must  all  go,  at 
.2  of  a  square  foot,  the  air  movement  which  could  be  main- 
tained is  at  the  rate  of  5,047  cubic  feet  per  hour,  which  is  a 
little  less  than  5,370  cubic  feet,  the  movement  we  have  as- 
sumed as  possibly  permissible.  This  reasoning  and  calcu- 
lation makes  it  clear  that  whenever  a  room  thus  ventilated 
has  the  drafts  in  the  heater  closed  the  necessary  air  move- 
ment must  at  once  fall  below  good  living  conditions  and 
hence  that  some  provision  ought  to  be  made  for  keeping  up 
the  air  supply  whenever  the  heater  is  not  running  with 
open  drafts.  There  is  often  a  check-damper  in  the  stove- 
pipe or  stove  which  may  be  opened  when  the  drafts  are 
closed  and  so  partly,  at  least,  keep  up  the  air  movement. 
Such  openings,  however,  as  usually  placed,  are  wasteful  of 
heat  because  they  throw  out  of  the  room  only  the  warmest 
air.  To  economically  use  the  room  heater  as  a  ventilating 
device  there  ought  to  be  attached  to  the  stovepipe,  as  rep- 
resented at  C  in  Fig.  39,  a  section  extending  down  to  near 
the  floor  level,  provided  with  a  close-fitting  damper,  so  that 
whenever  the  drafts  are  closed  in  the  stove  the  damper  in 
the  ventilating  section  may  be  opened,  and  thus  keep  up 
the  air  circulation,  drawing  out  of  the  room  only  the  cold- 
est air  it  contains.  Here,  then,  is  a  simple  arrangement  by 
which  many  a  poorly  ventilated  home  may  have  its  sani- 
tary conditions  very  materially  improved,  at  a  trifling  ex- 
pense when  compared  with  the  advantages  gained.  If  the 
room  to  be  ventilated  is  tightly  constructed  and  if  air  can- 
not be  borrowed  from  another  unoccupied  room  by  leaving 
the  door  ajar,  there  is  no  reason  why  fresh  air  intakes  may 
not  be  provided  on  the  same  plan  as  has  been  illustrated  for 
dairy  stables  in  Figs.  31-32,  pp.  72-74,  and  which  is  rep- 
resented at  AAAA,  BB,  in  Fig.  39.  In  providing  such  in- 


92 


Ventilation. 


takes  it  is  only  necessary  to  make  openings  through  the  sid- 
ing, as  represented  at  A,  between  pairs  of  studding,  cover- 
ing them  with  one-eighth  inch  mesh  galvanized  wire  net- 
ting, and  make  corresponding  openings  just  under  the 
ceiling  at  the  same  pair  of  studding,  covering  these  with 
white  enameled  4  by  12-inch  register  faces. 


Fig.  39.— Improvised  ventilation  system  for  an  ordinary  dwelling  already 

built. 

The  proper  course  to  take  in  installing  such  a  ventilation 
system  is  to  modify  the  heater  so  that  air  may  be  removed 
from  the  floor  level  as  already  described.  If  it  is  then 
found  that  an  air  change  of  sufficient  rapidity  takes  place, 
this  being  made  possible  through  unintentional  openings  in 
the  wall,  the  desired  result  has  been  attained  and  the  in- 
takes need  not  be  provided.  It  may  be  that  a  sleeping  room 
is  situated  as  represented  in  the  illustration,  through  which 
the  stovepipe  passes.  If  so  it  is  a  simple  matter  to  attach 
a  radiator  to  the  pipe  and  thus  without  extra  expense  ma- 


with   \Vnnn  Air  and  Ventilation  93 

terially  warm  the  room  and  improve  its  ventilation  if  only 
a  ventilating  flue  is  installed  as  indicated  at  D.  In  this 
case  we  have  assumed  that  th"iv  is  a  partition  and  that  the 
space  between  a  pair  of  studding  may  be  opened  just  above 
the  baseboard  and  covered  with  a  white  enameled  register 
face,  or  b.etter  still,  a  ivirist er  which  may  be  opened  and 
closed,  and  then  open  this  space  into  the  attic  or,  what 
would  be  much  better,  extend  up  through  the  roof  a  six- 
inch  galvanized  iron  pipe,  connecting  this  with,  or  extend- 
ing it  down  into,  the  space  between  the  studding  leading 
to  the  ventilating  register.  With  such  an  arrangement, 
with  the  fresh  air  intakes  indicated  in  the  figure  and  with 
the  radiator  as  shown,  we  have  an  ideal  sleeping  room  or, 
if  the  heater  below  is  large  and  the  room  above  small  and 
warmly  built,  it  may  be  a  comfortable  sitting  room  with- 
out the  expense  of  additional  heat. 

Dwellings  that  are  heated  with  hot  air  furnaces,  if  they 
are  thus  sufficiently  warmed,  are  usually  amply  ventilated 
so  long  as  the  warm  air  is  being  forced  in,  unless  the  faulty 
arrangement  has  been  adopted  of  returning  the  air  from 
the  heated  rooms  to  the  furnace  to  be  revolved  over  and 
over  again.  Such  a  system  is  very  bad  and  should  never 
be  used  unless  it  be  in  faultily  constructed  houses  where 
there  is  excessive  air  leakage  through  the  walls  or  in  windy 
weather  when  the  temperature  is  excessively  low.  In 
steam-heated  houses  and  in  those  heated  with  hot  water  by 
means  of  radiators  distributed  in  the  rooms  to  be  heated  the 
ventilation  may  be,  and  usually  is,  extremely  deficient, 
much  more  so  than  with  stove-heated  rooms,  for  the  reason 
that  with  these  systems  of  heating  there  may  be  provision 
neither  for  air  to  enter  nor  leave  the  room,  dependence  be- 
ing wholly  upon  leakage  through  the  walls  or  upon  the 
opening  of  windows  and  doors.  In  houses  thus  heated  some 
means  should  be  adopted  for  drawing  the  air  out  of  the 
rooms  at  the  floor  level,  even  if  nothing  better  than  the 
plan  suggested  for  the  second  floor  in  Fig.  39  at  D.  Fresh 
air  intakes  should  also  be  provided  and  if  possible  these 
should  be  so  placed  that  the  air  may  be  admitted  at  the 


94  Ventilation. 

ceiling  directly  above  the  radiators,  of  course  admitting  the 
air  from  low  down  outside,  as  at  A  B,  Fig.  39.  When  the 
fresh  air  intakes  are  thus  located  the  currents  of  warm  air 
rising  from  the  radiators  at  once  mingle  with  the  fresh 
air  entering,  so  that  this  is  immediately  and  directly  tem- 
pered. Of  course  very  many  variations  will  occur  in  mak- 
ing the  necessary  provisions  for  the  ventilation  of  houses 
already  built  but  enough  has  been  said  to  permit  such 
adaptations  as  may  be  called  for. 

Warming  and  Ventilation  for  New  and  Remodeled  Houses. 

As  has  been  earlier  said  the  real  problem  with  which  we 
have  here  to  deal  is,  how  nearly  can  we  maintain  the  air  of 
dwellings  at  the  normal  out  of  door  fresh  air  purity  with 
practicable  economy.  Accepting  this  statement  as  correct 
it  follows  that  if  pure  air  itself  can  be  economically  warmed 
and  used  as  the  medium  for  distributing  heat  through  the 
house  it  by  all  means  should  be  used,  rather  than  water,  as 
such,  or  in  the  form  of  steam.  All  but  two  of  the  twenty- 
eight  years  of  our  home-making  have  been  spent  in  two 
eight-room  houses,  each  with  two  stories  with  a  cellar  and  a 
floored  attic,  full  size.  Both  were  of  wood  with  walls  of 
2  by  4  studding  covered  with  tongued  and  grooved  fencing 
inside  and  out;  papered  and  sided  outside  and  lathed  and 
plastered  inside.  The  space  between  every  pair  of  studding 
was  ceiled  at  each  of  the  three  floors  to  prevent  the  circula- 
tion of  air  currents  between  rooms  and  attic  due  to  leakage 
through  walls  and  ceiling.  The  windows  were  all  made 
with  single  sash  but  double  glazed,  except  three  in  the  sec- 
ond house,  which  were  of  plate  glass.  Each  house  has  a 
single  chimney  beginning  in  the  cellar,  with  three  flues,  the 
central  one  12  by  12  inches,  for  the  furnace  and  kitchen 
range,  and  two,  one  on  each  side,  8  by  12  inches  for  ventila- 
tion. Both  houses  are  warmed  with  hot  air,  the  whole  lower 
floor  except  the  front  hall  being  maintained  at  64°  to  68° 
eighteen  hours  per  day.  Plants  have  been  grown  continu- 
ously in  bay  windows  and  on  window  brackets  in  both 


Heating  with  Warm  Air  and  Ventilation.  95 

houses  and  these  have  never  been  frosted,  they  have  never 
been  moved  from  the  brackets  to  prevent  freezing,  the  only 
precaution  taken  being  to  draw  the  curtains,  and  the  fur- 
nace has  never  received  attention  nights  after  retiring, 
usually  about  11  p.  m.  The  first  house  was  warmed  more 
than  fifteen  years  with  a  single  cast-iron  box  stove,  using 
four-foot  wood,  which  was  provided  with  a  drum  of  sheet- 
iron  and  bricked  in  like  a  furnace.  The  second  house  is 
warmed  with  a  No.  10  Economy  furnace  having  a  metal 
shield  and  using  coal.  The  fuel  bill  for  furnace  and  kitchen 
range  in  the  first  house  ranged  from  $55  to  $75  per  annum 
In  the  second  house  it  has  ranged  from  $64  in  the  earliei 
years,  increasing  with  the  price  of  coal,  to  $95.50  in  1908, 
using  hard  coal  with  some  wood  in  the  range,  and  gas  coke 
at  $6.75  per  ton,  and  "buckwheat"  coal  at  $6.50  per  ton, 
burned  together,  in  the  furnace ;  * '  chestnut "  at  $9  per  ton 
for  the  kitchen  range.  From  this  practical  experience,  cov- 
ering a  continuous  quarter  century  of  Wisconsin  climate 
we  feel  justified  in  saying  that  in  a  warm,  well-constructed 
house  it  is  entirely  practicable  to  economically  warm  an 
eight-room  dwelling  by  distributing  the  heat  with  warm 
air,  which  at  the  same  time  serves  the  purpose  of  thorough 
ventilation.  We  think  we  are  also  justified  in  saying  that 
if  there  is  ever  an  investment  that  pays  it  is  the  little  extra 
required  to  build  a  house  for  a  cold  climate  warm,  well  and 
thoroughly  ventilated,  if  your  own  family  is  to  live  in  it. 
The  saving  in  fuel  alone  is  high  interest  on  the  extra  money 
invested  and  you  get  the  healthful  conditions  and  comfort 
free.  But  we  would  not  advise  hot  air  warming  for  a 
house  poorly  constructed. 

Rooms  provided  with  fire-places  may  be  well  ventilated 
but  seldom  economically  warmed.  Steam  and  hot  water  are 
well  adapted  to  heating  all  types  of  dwellings  but  the  cost 
of  installation  and  that  of  maintenance,  excepting  for  fuel, 
is  relatively  high.  Good  ventilation  may  be  provided  with 
both  hot  water  and  steam  but  it  is  seldom  that  anything 
specific  is  done  along  this  line  and  when  proper  ventilation 
is  added  the  difference  in  cost  of  installation  over  warm- 


96  Ventilation. 

ing  with  air  becomes  still  greater.  The  perfect  heating  of 
a  house  with  warm  air  is  only  made  possible  by  first  pro 
viding  adequate  ventilation  because,  before  the  warm  air 
can  enter  a  room  the  cold  air  must  first  escape.  With  both 
hot  water  and  steam  the  house  is  most  easily  and  cheaply 
warmed  when  there  is  the  least  ventilation. 

We  shall  consider  first  the  warm  air  method  of  heating 
and  ventilation  because,  for  homes  of  moderate  cost,  and 
especially  in  the  country,  distant  from  plumbing  facilities, 
this  method  is  more  readily  managed  as  well  as  more 
cheaply  installed;  and  because  such  a  dwelling  must  then 
be  thoroughly  ventilated  if  it  is  warmed.  The  first  require- 
ment is  a  warm,  close  construction  and,  everything  consid- 
ered, the  cheapest  thoroughly  warm  construction  is  a  frame 
house  sheated  inside  and  out  with  low-grade  hemlock,  hav- 
ing the  outer  layer  of  sheating  covered  with  the  cheapest 
grade  of  roofing  tin  or  a  very  light  weight  of  galvanized 
iron  carefully  and  closely  nailed  with  edges  slightly  over- 
lapping to  thoroughly  exclude  the  air.  Walls  so  built  may 
then  be  treated  outside  and  in  with  any  desired  finish  to 
suit  the  taste.  The  two  thicknesses  of  %-inch  dry  lumber 
forming  air  spaces  between  the  studding,  even  if  the  boards 
are  not  matched  or  tongued  and  grooved,  so  long  as  the 
metal  is  used  to  thoroughly  stop  air  circulation,  will  give 
a  far  warmer  wall  than  building  papers  for  the  reason  that 
the  soft  wood  is,  both  because  of  its  texture  and  its  greater 
thickness,  superior  as  an  insulator  to  the  building  papers. 

All  spaces  between  studding  should  be  thoroughly  closed 
at  the  level  of  the  three  floors,  which  may  be  readily  and 
best  done  by  fitting  in  between  the  studding  rough  boards 
and  then  filling  in  with  about  six  inches  of  a  lean  mortar, 
or  concrete,  which  will  thoroughly  close  the  spaces  and 
make  the  walls  vermin-proof.  Storm  sash,  fitting  closely, 
on  all  but  plate  glass  windows,  should  be  provided.  Farm 
houses  should  all  have  a  cellar  and  floored  attic  the  full  size 
of  the  house.  Both  spaces  are  needed  for  both  service  and 
warmth  and  the  extra  cost,  considering  what  is  gained, 
should  not  lead  to  their  omission.  A  good  furnace  of  am 


Heating  with  Warm  Air  and  Ventilation.  97 


Jn    of    ceiling 


frafn  floor 


furnace 


Fig.  40.— Method  of  introducing  warmed  air  from  furnace  at  the  ceiling 
and  of  removing  the  fouled,  exhausted  and  cooled  air  from  the  floor, 
both  through  the  same  space  in  the  partition. 


98 


Ventilation. 


pie  size,  with  conveniences  for  storing  fuel,  should  occupy 
the  basement,  the  location  being  chosen  with  special  refer- 
ence to  the  most  direct  connection  between  the  furnace  and 
the  rooms  to  be  heated.  Both  the  warmed,  fresh  air  and 
the  fouled,  depleted  and  cooled  air 
may  be  most  advantageously  con- 
veyed through  the  partitions  in  the 
manner  represented  in  Fig.  40,  the 
warm  air,  as  represented  by  the  long 
arrow,  passing  from  the  furnace 
through  the  flue  and  entering  the 
room  at  the  level  of  the  ceiling  while 
a  corresponding  volume  is  forced  out 
from  the  floor  level  as  shown  by  the 
other  two  arrows. 

In  most  houses  constructed  in  the 
manner  described  it  will  only  be  nec- 
essary for  the  ventilating  flues  to  ex- 
tend into  the  attic  ventilating  all 
rooms  into  this  space  which  then 
makes  an  excellent  clothes  drying 
room  for  blustering  and  stormy 
weather.  The  air  may  pass  either 
directly  into  the  attic  from  each 
room,  or  it  may  be  passed  into  the 
room  above,  thus  warming  it  indi- 
rectly in  the  manner  represented  in 
Fig.  41.  In  this  case  the  warmed 
air  flue  extends  to  the  level  of  the 
ceiling  of  the'  room  on  the  second 
floor  where  it  is  closed,  the  air  leav- 
ing by  an  opening  at  the  ceiling  of 
the  first  floor.  With  this  arrange- 


Ba-semenT 


From  furnace 


Fig.  41.— Method  of  ventii-  ment  forced  ventilation  for  the  first 

lating    a     lower    room  .  .  . 

into  an  upper  one.  floor  is  provided.  The  flue1  being  all 
the  time  filled  with  warm  air  heats  the  surrounding  air 
in  the  same  space  thus  giving  a  column  18  or  20  feet  long 
to  aid  in  producing  a  draft  out  of  the  lower  room.  The 


Heating  with  Warm  Air  and  Ventilation. 


99 


Attic 


upper  room  may  thus  be  largely  or  wholly  warmed  without 

extra  heat.    To  secure  this  result  the  space  between  the  pair 

of  studding  is  made  sufficiently  large,  as  seen  in  Fig.  40,  to 

contain  the  warmed  air  flue  and  provide  ample  room  to  act 

as  a  ventilator.     Before  lathing  the 

partition  the  hot  air  flue  is  installed 

and    the    space    closed    by    covering 

with  roofing  tin  or  a  light  weight  of 

galvanized  iron.     This  makes  a  safe 

arrangement  and  permits  the  hot  air 

riue  to  have   a  single   wall.     At  the 

same  time  a  tight-walled  ventilating 

shaft  is  provided  for  the  lower  room. 

"With    this    arrangement   it   is   neces- 

sary  to   provide   ventilation    for   the 

upper  room.     This  may  be  done  by 

opening   into   the   space   between   an- 

other pair  of  studding  letting  it  dis- 

charge into  the  attic.     If  more  heat 

is  desired  for  the  upper  room  a  plan 

similar  to   that  represented   in   Fig. 

42  may  be  adopted,  which  is  an  ex- 

tension of  the  principle  of  Fig.  41. 

If  only  direct  heating  and  direct 
ventilation  are  desired  then  the 
method  will  be  essentially  the  same 
as  in  Fig.  41,  the  hot  air  flue  extend- 
ing to  the  attic  floor  in  either  case'  so 
as  to  secure  the  maximum  forcing  ef- 
fect. The  chief  objection  to  the 
methods  of  warming  and  ventilating 
the  house1  as  has  been  described  is 
the  comparatively  small  motive  power 
for  ventilation  at  times  when  there 
is  no  fire  in  the  furnace.  It  is  true, 
that  at  such  times  the  house 


Coo/Get 


•Sec  no/  floor 


|  Seen 


'st  floor 

Basement 
From  furnac  e 

Fig.  42.— Method  of 
heatinsr  upper  room 
and  ventilating  Into 
the  attic. 


is  more  or  less  thrown  open  through  doors  and  windows. 

Another  method  for  direct  heating   and  ventilation  is 
represented  in  Fig.  43  where  there  is  a  central  chimney  of 


100 


Ventilation. 


brick,  with  flue  lining,  surrounded  with  a  ventilating  shaft 
made  of  galvanized  iron  nailed  directly  to  the  studding  be- 
fore lathing.  In  this  diagram  four  rooms  directly  adjoin- 
ing the  chimney  are  represented  as  being  ventilated  at  one 
floor  level.  Distant  rooms  on  the  same  floor  may  be  con- 
nected with  the  same  flue  by  leading  a  fouled  air  duct  under 
the  floor  cut  into  the  ends  of  the  joists  under  the  partition, 
or  in  the  space  between  two  joists  if  they  extend  in  the 
right  direction.  If  it  is  so  desired  these  ventilators  may  be 
finished  in  imitation  of  fire  places. 


Fig.  43.— Ventilating  flue  oi!  galvanized  iron  surrounding  the  chimney  and 
utilizing  the  warmth  of  the  smoke  flue  to  force  the  draft  in  the  ven- 
tilator. A  flue  lining  is  used  inside  the  brick. 

If  so  desired  the  ventilating  flue  may  begin  at  the  sec- 
ond floor  or  even  at  the  attic  floor  when  it  is  desired  to 
warm  the  upper  rooms  with  the  exhaust  air  from  the  lower 
ones.  Such  a  plan,  however,  cannot  derive  as  much  advan- 
tage from  the  warmth  of  the  chimney. 

If  it  is  desired  to  heat  with  either  steam  or  with  hot 
water  some  system  of  ventilation  should  by  all  means  be  in- 
stalled at  the  same  time  and  this  can  be  done  without  dif- 
ficulty and  without  greatly  increasing  the  cost  as  will  be 
readily  seen  from  a  study  of  Fig.  44.  In  this  type  of 
house  warming  the  radiators  should  be  placed  under  the' 
fresh  air  intakes  where  the  warmed  air  will  rise  where  the 
cold  air  enters  and  falls. 

When  fresh  air  intakes  are  provided  for  each  room  to  be 
occupied  and  ventilators  are  provided  in  some  one  of  the 


Ventilation  with  Steam  and  Hot  Water  Heat.      101 

ways  already  Ascribed  and  illustrated  ideally  sanitary 
homes  will  be  provided  so  far  as  fresh  air  is  concerned. 
The  air  may  exhaust  through  a  fireplace,  through  a  shaft 


Fij,'.- 44. —Ventilation   of  a  house  \vanned   with  steam   or  with  hot  water. 

built  about  the  chimney  as  illustrated  in  Fig.  43,  or  by 
means  of  flues  placed  in  the  partitions  and  exhausting  into 
the  attic  or  directly  through  the  roof. 

In  the  next  illustration  is  shown  a  type  of  house  which 
is  extremely  well  designed  to  meet  the  needs  and  comforts 
of  country  homes.  It  may  be  made  larger  or  smaller;  the 
verandas  and  decorations  may  be  altered  to  suit  the  taste 
or  expense ;  for  a  smaller  house  the  kitchen  may  be  omitted 
and  one  of  the  other  rooms  adapted  to  this  purpose.  It  is 
a  type  which  lends  itself  well  to  economy  of  construction, 
to  economy  of  heating,  and  it  may  be  well  ventilated  by 
any  system  of  heating  if  proper  attention  is  given  to  the- 
matter  when  laying  out  its  construction. 


102 


Ventilation. 


••  •> 'ir  •  -  ,..r.  ir  -  'j,,.,,;,  •     <  •«»  • ' '  ;  ••  -  ." .*•;;' ',•;.  » "-  "' 


45  and  46. — Elevation  and  floor-plan  of  house  readily  warmed  and 
ventilated. 


HEATING  AND  VENTILATION  OF  RURAL  SCHOOL-HOUSES  AND 
CHURCHES. 

Now  that  concrete  construction  has  been  so  far  perfected 
and  cheapened  it  appears  to  the  writer  that  we  are  in  posi- 
tion to  build  all  new  country  school-houses  and  churches 
in  a  manner  which  will  permit  of  their  being  both  ideally 
warmed  and  thoroughly  ventilated.  To  have  conditions 
right  both  school  and  church  should  have  thoroughly  warm 
floors  and  they  should  have  a  moderately  warm  atmosphere 


Warming  and  Ventilation  for  Rural  Schools.       103 

which  is  being  rapidly  and  continuously  changed.  To 
secure  these  ends  it  is  necessary  to  remove  the  heater  to  a 
basement  and  then  permit  none  of  the  air  which  comes  in 
contact  with  it  to  become  a  part  of  the  air  supply.  Thisr 


Fig.  47.— Warming  and  ventilation  for  a  country  school  or  church 

in  our  judgment,  may  be  readily  done  and  more  econom- 
ically than  warming  with  poor  ventilation  is  now  accom- 
plished. 

Describing  first  a  country  school-house  built  along  these 
lines,  as  represented  in  Fig.  47,  there  is  constructed  a  mon- 
olithic concrete  basement,  including  the  first  floor,  using  in 
the  walls,  for  warmth,  hollow  building  tile  bedded  in  the 
concrete  mass.  These  tile  are  cheaper  than  the  concrete- 


104  Ventilation. 

and  they  offer  the  most  expeditious  way  of  securing  a  hol- 
low wall.  On  the  walls  is  constructed  a  reinforced  con- 
crete ceiling  and  floor,  the  ceiling  built  first  and  covered 
closely  with  a  layer  of  hollow  tile  carefully  laid  in  series 
so  as  to  form  continuous  air  ducts  through  which  to  circu- 
late heated  air  for  the  purpose  of  warming  the  floor  and 
through  it,  as  a  radiator,  the  room  above.  A  cement  floor  is 
then  laid  over  the  tile. 

Across  the  center  of  the  floor-ceiling  the  tile  would  be 
omitted  over  a  strip  three  or  more  feet  wide  forming  a 
broad  duct  into  which  the  heater  casing  communicates  so 
as  to  flood  all  of  the  tile  with  hot  air  and  thus  warm  the 
floor.  At  the  two  ends  of  the  building  a  similar  but  nar- 
rower duct  is  formed  which  permits  the  heated  air  to  es- 
cape and  return  to  the  heater,  thus  providing  means  for  the 
continuous  circulation  of  the  same  mass  of  air  on  the  prin- 
ciple of  the  circulation  of  water  or  steam.  The  heater 
room  should  have  tight  walls  except  near  the  floor  so  as  to 
confine  a  column  of  heated  air,  this  being  the  motive  power 
for  maintaining  the  circulation.  The  air  then  enters  the 
heater  chamber  at  C,  Fig.  47,  passing  to  the  ceiling  to  be 
distributed  through  the  various  channels  and  is  again  re- 
turned to  repeat  the  circuit  indefinitely. 

The  room  to  be  warmed  and  ventilated  above  is  closely 
constructed  and  finished  with  a  ceiling  provided  with  open- 
ings AA  through  which  the  air  may  enter  from  the  outside 
as  indicated  by  the  arrows  A  A  AA;  the  air  rising  between 
the  studding  and  along  the  spaces  formed  by  the  joists. 
The  floor  above  these  joists  must  be  very  tight  and  warm. 
The  air  everywhere  in  contact  with  the  floor  is  warmed  and 
forced  to  circulate  as  it  would  be  if  steam  or  hot  water  rad- 
iators were  used. 

The  chimney  is  best  made  of  suitable  size  wrought  iron 
pipe  or  boiler  tubing  or  else  of  a  heavy  weight  of  sheet  iron 
riveted  and  this  should  occupy  the  center  of  the  ventilating 
shaft,  which  is  best  made  of  galvanized  sheet  iron.  With 
this  construction,  the  air  entering  the  shaft  from  the  room 
at  BB  is  forced  out  by  the  waste  heat  of  the  smoke  flue ;  and 


}Yarniin<j  and -Ventilation  for  Rural  Schools.       105 

fresh  air  directly  from  outside  is  thereby  continuously 
drawn  in  through  the  intakes  AA.  In  the  illustration  E 
suggests  a  way  in  which  a  hot  air  radiator  may  be  installed 
furnishing  a  convenience  for  hand  warming  if  desired; 
here  warm  air  simply  circulates  from  and  to  the  furnace 
and  does  not  escape  into  the  school  room.  It  may  be  made 
in  cement. 

The  great  advantage  of  heating  from  the  basement  in 
some  manner  is  that  it  insures  a  thoroughly  warm  floor. 
AY  hen  the  feet  are  adequately  and  continuously  warm  a  lower 
surrounding  air  temperature  is  admissible  and  this  makes  it 
quite  certain  that  a  larger  air  circulation  will  be  maintained 
which  is  the  important  point  in  every  school  room.  It  fol- 
lows, therefore,  that  even  if  the  heater  is  not  placed  in  the 
basement  there  should  be  a  good  cellar  under  the  whole 
floor  with  warm  walls  and  deep  enough  not  to  freeze  and 
to  serve  as  a  store  room  for  kindling  and  fuel  and  to  help 
keep  the  floor  more  comfortable  to  the  feet.  If  a  cellar  will 
not  be  built  then  a  damp-proof  cement  floor  laid  directly  on 
the  ground,  which  may  be  covered  with  a  layer  of  boards 
or  linoleum  if  desired,  is  far  warmer  and  more  sanitary  as 
well  as  enduring,  than  many  of  those  now  in  use. 

If  the  heater  is  in  the  school  room,  its  proper  place  is 
central  on  the  floor  but  near  the  entrance.  It  should  be 
surrounded  on  three  sides  with  a  metal  shield,  open  toward 
the  door,  to  cut  off  direct  radiation  from  the  children.  The 
smoke  flue  should  rise  straight  out  through  the  roof,  and  it 
should  be  surrounded  by  the  ventilating  flue  as  represented 
in  Fig.  48,  drawing  out  the  fouled  air  at  the  floor  level  and 
from  behind  the  screen  at  A.  The  fresh  air  should  be  in- 
troduced through  the  ceiling  rising  through  the  walls  from 
low  down  outside,  Fig.  47,  discharging  largely  in  the  -front 
of  the  room  and  over  the  heater  where  it  may  mingle  di- 
rectly with  the  warmest  air;  or  it  may  be  taken  directly 
down  through  the  roof  in  the  manner  shown  at  BB  where 
the  duct  is  provided  with  a  revolving  cowl  at  the  top,  to 
utilize  fully  the  wind  pressure,  and  with  an  air  trap  at  the 
lower  end  to  prevent  the  escape  of  warm  air.  In  still  an- 


106 


Ventilation. 


other  way  the  air  may  be  let  in  beneath  the  floor  and  directly 
up  under  the  stove  and  inside  the  jacket.  The  advantage  of 
the  method  of  taking  fresh  air  represented  in  Fig.  48  is 


Fig.  48.— Ventilation  of  school  room  which  must  contain  the  heater. 

that  when  there  is  little  or  no  fire  in  the  heater  to  force  a 
draft,  the  combined  effect  of  wind  pressure  and  wind  suc- 
tion may  be  utilized.  A  damper  in  the  ventilating  flue  at 
C  permits  the  amount  of  air  moving  to  be  controlled  at  any 
time. 


Ventilation  of  Stables.  107 


Ventilation  of  Dairy  Stables. 

In  the  details  of  stable  ventilation  there  must  be  almost 
endless  variation  to  meet  individual  conditions.  Notwith- 
standing this,  the  principles  governing  construction  are  few 
and  have  already  been  stated  in  general  terms.  Because  the 
motive  power  usually  available  in  stable  ventilation  is  both 
small  and  variable  in  intensity  it  is  of  the  highest  impor- 
tance that  strict  attention  be  given  to  all  essential  details  of 
construction  necessary  to  adequate  efficiency. 

The  one  detail  of  paramount  importance  in  every  system 
of  stable  ventilation  is  the  outtake  flue.  It  is,  in  function, 
nothing  more  than  a  chimney ;  it  should  be  nothing  less  than 
one  of  the  best  type,  barring  the  single  feature  that  it  need 
not  be  fire-proof.  Whatever  is  counted  essential  in  a  good 
chimney  must  be  held  even  more  essential  to  a  good  stable 
ventilating  flue;  and  whatever  would  be  ruled  out  of  the 
construction  of  a  good  chimney  must  be  more  scrupulously 
excluded  here,  and  for  the  simple  reason  that  the  motive 
power  at  best  is  small  when  compared  with  that  available 
in  most  good  chimneys.  The  walls  of  the  outtake  should  be 
so  made  as  to  be  and  to  remain  permanently  air-tight  except 
where  openings  are  provided.  This  feature  is  essential  in 
order  that  only  air  from  the  space  to  be  ventilated  shall  con- 
tribute to  the  current  passing  through.  In  practice  many 
outtakes  have  been  constructed  so  openly,  above  the  stable 
to  be  served,  that  their  efficiency  is  thereby  greatly  im- 
paired. Next  in  importance  is  an  ample  cross-section,  uni- 
formly so  throughout  its  length.  If  the  outtake  is  con- 
stricted at  any  point  the  smallest  section  determines  its  ca- 
pacity. Keducing  the  diameter  of  a  cylindrical  flue  one- 
half  makes  the  pressure  necessary  to  force  a  given  volume 
of  air  through  nearly  four- fold,  while  doubling  the  diameter 
permits  one-fourth  the  pressure  to  do  the  work.  The  out- 
take which  is  circular  in  cross-section  or  square  is  to  be  pre- 
ferred to  one  long  and  narrow,  because  the  wall  surface  for 
cooling  the  air  and  for  friction  is  relatively  materially  less 


108 


Ventilation. 


and  this  means  less  loss  of  pressure  and  hence  greater  flow 
when  the  motive  power  is  small.  The  oblong  section  may  be 
chosen  if  conveniences  require  it,  but  then  the  area  should 
be  made  relatively  greater.  The  motive  power  for  ventila- 
tion due  to  temperature  differences  increases  with  the  hight, 
and  the  suctional  effect  of  the  wind  does  also,  but  the  loss  of 


No.£8  Galvanized  Iron. 


Lumber  j£  th  icK 


•Fig.  49. — Showing  manner  of  constructing  outtake  flue,  using  2x4' s  for 
corners  and  galvanized  iron  for  walls,  covered  with  wood  if  greater 
warmth  Is  important. 


power  due  to  friction  increases  with  the  length  and  with 
bends.  The  outtake  should,  therefore,  be  free  from  angles 
wherever  practicable. 

Galvanized  iron  is  the  best  available  material  with  which 
to  construct  the  walls  of  outtake  flues,  and  they  are  most 
simply  made  in  the  manner  shown  in  Fig.  49.  The  sheets  of 
metal  may  be  obtained  in  widths  from  24"  to  36"  and  in 
lengths  of  8'  or  10'.  The  metal  should  be  nailed  closely 
as  represented  in  the  upper  part  of  the  figure,  using  small 
galvanized  wire  nails  to  avoid  rusting  out.  If  the  flue  is  in 
an  exposed  situation  it  may  be  covered  with  wood,  as  shown 


Construction  of  0  Makes  and  Intakes. 


109 


in  the  lower  part  of  the  cut,  to  lessen  the  cooling  of  the  air 
during  its  passage,  or  the  flue  may  be  made  larger  to  com- 
pensate for  loss  of  power  through  loss  of  heat.  Where  the 
ends  of  sheets  meet  pieces  should  be  cut  in  between  the  up- 
rights into  which  to  closely  nail  the  ends,  overlapping  about 
an  inch. 


Fig.  .50.— Severn  1  typos  of  intakes.  1,  utilizes 
sptir-c  between  studding;  2,  made  of.  galvan- 
ized iron  shaped  as  at  a;  3,  constructed  in 
masonry  wall;  4,  for  basement  stable  al- 
ready built;  5,  utilizing  space  between 
double  windows. 


At  present  prices  the  metal  is  cheaper  than  paper  for  the 
reason  that  only  a  heavy  grade  of  acid  and  water  proof 
variety  is  permissible  and  this  can  only  safely  be  used  be- 
tween two  layers  of  tongued  and  grooved  boards.  Without 
this  precaution  the  paper  will  warp  and  tear  itself  loose  and 
it  is  liable  in  any  case  to  disintegrate  in  time,  leaving  leaks 
between  the  boards. 

The  construction  of  the  intakes  is  not  a  matter  of  such 
critical  importance.  Almost  any  sort  of  flue  will  answer. 
They  should  be  numerous,  weljl  distributed  on  all  sides  of  the 
stable  if  practicable,  and,  in  order  that  they  may  trap  the 
escape  of  the  warm  air  of  the  stable,  the  outside  opening 
should  be  three  or  more  feet  below  the  inlet.  Their  aggre- 
gate cross-section  should  equal  if  not  exceed  that  of  the  out- 


110  Ventilation. 

takes,  unless  the  stable  has  an  open  construction,  for  the 
reason  that  air  can  continuously  leave  the  stable  no  faster 
than  it  can  enter.  Small  intakes  distributed  at  intervals  of 
about  12  feet  are  to  be  preferred  to  large  ones,  there  being 
then  a  better  commingling  of  the  cold  with  the  warm  air 
and  less  danger  of  cold  drafts. 


Ventilation   of   Dairy    Stables. 

In  January,  1889,  we  received  a  request  to  design  a  barn 
for  a  dairy  farm  which  would  accommodate  80  cows  and  10 
horses  and  which  would  permit  of  driving  behind  the  cows 
in  cleaning  and  in  front  in  feeding.  A  silo,  granary  and 
storage  space  for  roughage  sufficient  for  all  the  stock  were 
desired  and  it  was  specified  that  all  should  be  under  one 
roof,  every  thing  conveniently  accessible  and  not  relatively 
expensive.  The  barn  was  built  during  the  summer  of  the 
same  year  on  the  farm  of  Mr.  C.  E.  King,  Whitewater,  Wis., 
to  accommodate  98  cows,  and  was  the  first  structure  to  con- 
tain the  ventilation  system  for  stables  here  described.  In 
describing  the'  barn  for  the  Seventh  Annual  Report  of  the 
Wis.  Agr.  Exp.  Station  we  said:  Whatever  conveniences 
a  barn  may  contain  these  should  in  no  way  interfere  with 
the  best  performance  of  the  animals  housed.  It  should  be 
so  built  that  the  heat  given  off  by  the  animals  housed  shall 
be  sufficient  to  maintain  the  best  stable  temperature  and  at 
the  same  time  admit  of  ample  ventilation.  It  should  ad- 
mit the  necessary  amount  of  light  to  all  the  animals- and 
be  so  constructed  as  to  reduce  care-taking  to  a  minimum. 

The  barn  as  erected  is  represented  in  Fig.  51  and  was  of 
the  cylindrical  type,  92  feet  in  diameter,  two  stories,  and 
costing  at  that  time,  with  the  average  price  of  lumber  $15 
per  thousand,  a  little  less  than  $2,400,  not  including  the 
board  of  the  carpenters.  The  manner  in  which  the  ventila- 
tion was  secured  is  shown  in  Fig.  52  where  the  32  spaces 
between  the  studding  in  the  walls  of  the  silo,  34  feet  high, 


Ventilation  of  Dairy  Stables. 


Ill 


are  utilized  as  outtakes,  having  an  aggregate  cross-section 
of  35  square  feet.    Here,  not  only  are  these  outtakes  cen- 


Fig.   51.— First   barn  in    which   the   King  system  of  ventilation  was  in- 
stalled,  in  1889. 

trally  located  in  the  warmest  portion  of  the  barn  with  the 
cows  grouped  about  them,  but  the  warmth  of  the  inner  walls 
of  the  flues,  maintained  by  the  heating  of  the  silage,  is 


Fig.  52.— Showing  cows  arranged  in  two  rows  centrally  nhout  oiirrakes 
in  the  entire  circumference  of  the  silo,  and  with  intakes  for  fresh 
air  between  every  fourth  pair  of  studding  in  the  wall. 


112 


Ventilation. 


utilized  as  a  constant  motive  power  to  force  the  air  move- 
ment through  them.  Intakes  for  fresh  air  are  provided  be- 
tween every  fourth  pair  of  studding  around  the  entire  cir- 
cumference of  the  barn.  By  this  arrangement  there  is  se- 


Fig.  53.— Showing  the  inverted-Y  type  of  outtake  used  in  the  dairy  barn 
at  Wisconsin  Agr.  Bxp.  Station.  A  A  A  is  the  outtake  flue;  C.  C. 
provisions  for  cooling  stable  and  reinforcing  the  draft.  Intakes  tor 
fresh  air  at  ceiling  represented  at  B. 

cured  'a  continuous  flow  of  fresh  air  in  at  the  ceiling  of  the 
stable  uniformly  past  every  animal  while  the  fouled  and  im- 
poverished air  is  at  the  same  time  being  drawn  off  at  the 
floor  level.  A  thoroughly  adequate  and  continuous  air  move- 
ment through  the  stable  is  thus  secured  without  extra  cost 
of  construction. 


Ventilation  of  Dairy  Stables. 


113 


The  ventilation  system  installed  in  the  dairy  barn  of  the 
"Wisconsin  Agr.  Exp.  Station,  which  accommodates  38  cows, 
is  represented  in  Fig.  53.  In  this  case  the  outtake  is  a 
single  central  shaft  in  the  shape  of  an  inverted  Y  as  seen 


Fig.  54.— Showing  a  pair  of  U-shaped  outtakes  adapted  to  stables  for  60 
takes;  C  ceiling  register  in  a  cross-arm  joining  the  two  sides  of  the 
to  80  cows.  A  A  A  A  A  are  the  two  outtakes:  B  B  B  B  are  the  in- 
outtake. 

at  AAA  with  a  small  outtake,  C,  opening  at  the  ceiling  for 

use  in  conjunction  with  the  other  registers  C  to  be  opened 

only  during  still  weather  when  the  stable  is  too  warm  or  the 

movement  of  air  too  slow.    The  fresh  air  intakes,  shown  at 

B  by  the  series  of  small  rectangles  with  arrows,  are  24  in 

number,  each  4x12  inches,  the  air  entering  just  above  the 

sill  outside,  and  rising  between  as  many  pairs  of  studding. 

A  more  effective  arrangement  for  the  outtakes  is  repre- 

8 


114 


Ventilation. 


sented  in  Fig.  54,  which  shows  two  U-shaped  flues  rising 
from  just  behind  the  manger  between  two  cows  in  a  stable 
adapted  to  60  or  80  cows,  seen  at  AAAAA,  with  a  ceiling 
register  at  C  for  use  when  the  stable  is  too  warm  and  to  re- 
inforce the  draft  when  needful.  For  20  cows  and  for  40 


Pig.  55.— Showing  single  straight-away  outtakes  which  avoid  all  angles 
and  render  possible  the  strongest  draft. 

one  of  these  U-shaped  outtakes  would  answer,  located  near 
the  center  of  the  stable. 

A  still  better  and  perhaps  the  best  practicable  arrange- 
ment of  the'  outtakes -is  represented  in  Fig.  55  where  each 
shaft  is  straight  and  rises  directly  through  the  roof  and 
above  the  level  of  the  ridge  to  be  fully  out  of  the  zone  of  air 
currents  which  tend  to  produce  down  drafts. 

In  the  next  illustration  the  outtakes  are  straight  but  oc- 


Ventilation  of  Dairy  Stables. 


115 


cupy  positions  against  the  outer  walls.  Here  they  are  L'ss 
in  the  way  but  they  must  be  projected  farther  above  the 
roof  and  are  more  unsightly  as  well  as  being  where  the  ani- 
mal heat  is  less  efficient.  In  barns  already  built,  and  es- 
pecially if  the  animals  are  few  and  a  cupola  exists,  this  plan 
may  be  safely  adopted  with  the  modification  that  the  out- 
takes  may  be  carried  up  to  the  roof  inside  and  allowed  to 
stop  there  or  be  turned  toward  or  to  the  cupola. 


Fig.  56.— Showing  straiglit-away  outtakes  placed  against  the  wall. 

In  Fig.  57  the  arrangement  differs  from  that  of  Fig.  55 
in  having  the  lower  ends  of  the  outtakes  against  the  outer 
wall,  thus  removing  them  from  between  the  cows.  There  is 
another  partial  advantage -to  offset  the  loss  due  to  greater 
length  and  angles.  If  the  under  face  of  the  outtake  along 
the  ceiling  is  made  of  galvanized  iron  the  warmest  air  of  the 
stable  will  come  continually  against  it  and  thus  keep  it  warm 
to  assist  in  forcing  the  draft. 

"Where  there  is  a  lean-to  stable,  as  represented  in  Fig.  58, 


116 


Ventilation. 


the  outtake  may  be  constructed  inside  the  main  barn  and 
terminated  as  represented,  or  it  may  be  carried  under  the 
roof  to  the  cupola  or  to  the  ridge.  If  only  a  few  animals  are 


Fig.    57.— Showing  manner  of  placing  only   the  lower   ends   of   the  out- 
takes  against  the  outer  walls. 

to  be  supplied  the  flue  may  be  made  relatively  large  in  cross- 
section  and  terminated  in  the  main  barn  just  under  the 
roof. 

In  barns  already  built  without  special  provision  for  ven- 
tilation it  may  be  possible  to  utilize  one  or  more  of  the  hay 
chutes,  if  they  exist,  by  extending  them  to  the  floor,  as  sug- 
gested in  Fig.  59,  to  prevent  the  loss  of  air  at  the  ceiling. 
Lifting  or  swinging  doors  may  then  be  provided  to  be  al- 
ways closed  except  when  the  hay  is  being  put  down. 


Ventilation  of  Dairy  Stables. 


11T 


58.— Showing  method  of  ventilating  a  lean-to. 


Pig.  59.— Showing  method  of  utilizing  a  hay  chute  as  an  outtake- 


118 


Ventilation. 


The  provisions  for  taking  fresh  air  into  the  stable 
wherever  the  walls  are  hollow  and  rise  four  or  more  feet 
above  the  ground  have  been  sufficiently  illustrated  in  pre- 
ceding figures.  In  stables  having  solid  masonry  walls  al- 
ready constructed  the  fresh  air  intakes  may  be  made  in  the 
manner  illustrated  in  Fig.  60  where  an  intake  flue  is  shown 


Fig.  60.— Showing  two  methods  of  admitting  fresh  air  to  basement 
stable  C  and  D.  The  two  hay  chutes  and  the  small  ceiling  ventilator 
are  not  intended  to  illustrate  proper  outtakes. 

at  C,  the  large  arrow  indicating  the  course  of  the  air  cur- 
rent in  entering  the  stable.  Here  the  space  between  a  pair 
of  studding  is  closed  off  at  a  hight  of  4  or  5  feet  and  in  it 
is  inserted  a  light  tin  10  inch  pipe  flattened  to  4  inches  and 
inserted  in  an  opening  through  the  stable  ceiling.  The 
space  is  then  ceiled  up  and  a  4-inch  opening  cut  in  the  out- 
side wall  about  the  length  of  the  long  diameter  of  the  tin 
flue,  for  the  entrance  of  air.  The  number  and  distribution 
of  these  should  be  the  same  as  in  the  case  of  the  ordinary 
intakes. 


Area  of  Cross-section  of  Ventilating  Flues.        119 

On  the  left  side  of  the  figure  is  illustrated  another  way 
of  providing  intakes.  The  space  between  a  pair  of  stud- 
ding is  closed  at  the  proper  hight  and  all  but  the  upper 
portion  is  divided  by  a  partition  in  the  manner  shown. 
This  partition  is  most  simply  formed  out  of  a  piece  of  light 
galvanized  iron  of  proper  width  and  hight  having  the  bot- 
tom and  the  two  sides  turned  at  a  right  angle  for  the  pur- 
pose of  nailing  it  in  place.  Where  the  siding  of  the  barn  is 
nailed  in  place  vertically  intakes  may  be  formed  by  using 
two  strips  of  galvanized  iron  formed  up  as  just  described, 
nailing  them  on  opposite  sides,  each  with  the  open  end 
down,  thus  forming  two  arms,  one  outside  and  the  other  in- 
side extending  through  the  stable  ceiling  with  the  two  con- 
necting at  the  top  through  an  opening  cut  in  the  siding. 

Where  masonry  walls  are  being  constructed  for  stables 
the  intakes  are  readily  formed  in  the  building  of  them  by 
placing  in  the  wall  a  proper  form.  The  forms  may  be  hol- 
low building  tile,  drain  tile  or  shapes  in  wood  providing  the 
desired  capacity,  simply  set  in  the  place  desired  and  the 
wall  built  about  them. 

From  the  statements  made  relating  to  the  principles  of 
ventilation,  in  the  preceding  section,  it  follows  that  the  area 
of  cross-section  of  both  the  outtakes  and  the  intakes  must  de- 
pend in  an  important  degree  upon  the  hight  of  the  out- 
take.  If  the  ventilating  shaft  is  low  then  it  must  have  a 
sufficiently  larger  cross-section  to  compensate  for  the  less 
velocity  of  air  current  in  the  flue  which  is  always  associated 
with  short  shafts.  In  my  earlier  writing  it  was  stated  that 
a  ventilating  flue  2x2  feet  through  which  the  air  moved  at 
the  rate  of  295  feet  per  minute,  or  a  little  more  than  3  miles 
per  hour,  gave  sufficient  air  for  20  dairy  cows.  This  state- 
ment does  not  mean  that  any  flue  2x2  feet  will  carry  out  of 
the  stable  sufficient  air  for  20  cows.  Such  a  flue  can  do  so 
only  when  the  velocity  of  the  air  current  is  rather  more  than 
3  miles  per  hour. 

Let  us  refer  back  to  the'  table  on  page  56.  Take  the 
column  for  the  20  foot  outtake.  These  cubic  feet  of  flow 
per  hour  for  the  one-foot  flue  also  mean  velocity  in  feet  per 


120  Ventilation. 

hour,  and  hence  if  we  divide  these  numbers  by  60  the  result 
will  be  the  velocity  in  feet  per  minute.  Doing  this  we  get 
the  round  numbers  97,  307,  434,  532,  and  615  feet  respect- 
ively for  stables  which  are  warm  enough  so  that  the  air  in 
the  flue  is  1°,  10°,  20°,  30°,  and  40°  warmer  than  the  air 
outside.  But  these  are  theoretical  velocities,  no  allowance 
having  been  made  for  friction  and  other  resistance  to  flow. 
It  is  quite  likely  that  the  actual  velocities  might  not  be  more 
than  one-half  those  computed.  If  so  then  only  the  last  three 
differences  in  temperature  between  the  air  in  the  outtake 
and  that  out  doors,  namely  20°,  30°,  and  40°  will  permit  a 
20-foot  flue  to  supply  air  enough  for  20  cows  when  its  size 
is  2x2  feet.  As  the  cows  must  breathe  all  of  the  time  and  as 
there  are  times  when  there  is  little  or  no  effective  wind,  dif- 
ference in  temperature  must  chiefly  determine  the  dimen- 
sions of  the  outtake  and  intakes  and  the  two  should  be  ap- 
proximately equal  in  area  of  cross-section.  The  difference 
between  the  stable  temperature  and  that  of  the  outside  air 
as  given  on  page  66  ranges  from  24°  to  61°  and  averages 
39°.  The  temperature  in  the  ventilating  flue  will  certainly 
average  materially  below  that  in  the  stable  and  as  it  is  the 
temperature  in  the  ventilating  flue,  compared  with  that  out- 
side, which  determines  the  draft,  the  mean  effective  differ- 
ence of  temperature  will  be  found  to  average  materially  less 
than  39°  and  probably  nearer  20°  than  30°.  With  a  tem- 
perature difference  ofv25°  a  30-foot  shaft  will  give  just 
about  the  required  flow.  The  conclusion  which  should  gov- 
ern practice,  therefore,  is :  Outtakes  and  intakes  for  horses 
and  cows  should  provide  not  less  than  30  square  inches  per 
head  when  the  outtake  has  a  hight  of  30  feet;  if  the  outtake 
is  shorter  the  area  should  ~be  greater,  if  higher  it  may  be 
less.  A  20-foot  outtake  would  require  about  36  square 
inches  per  head  instead  of  30. 

Ventilation  for   Swine  and   Sheep. 

In- the  construction  of  quarters  for  both  swine  and  sheep 
it  has  been  the  practice  to  build  lower  ceilings  and  quite 


Ventilation  of  Piggery.  121 

generally  lower  stables  for  them  than  for  horses  and  cattle. 
Both  kinds  of  animals  being  small  and  given  the  freedom  of 
the  stable  in  common,  over-crowding  has  been  more  frequent 
and  this  practice,  coupled  with  the  lower  ceilings,  has  re- 
sulted in  their  suffering  from  the  effects  of  insufficient  ven- 
tilation oftener  than  horses  and  than  cattle,  except  in  later 
years  when  the  number  of  individuals  in  a  herd  has  been 
greatly  increased.  Sheep  are  extremely  well  protected  from 
cold  by  their  heavy  fleece  of  wool ;  so  too,  are  swine  of  cold 
climates,  when  in  good  condition,  by  the  thick  layer  of  fat 
interposed  between  the  skin  and  the  more  vital  parts,  serv- 
ing the  double  purpose  of  nourishment  stored  against  need 
and  a  weather  garment.  We  doubt  very  much,  however,  that 
these  protections  mean  these  animals  are,  necessarily,  best 
maintained  in  severe  climates  with  little  or  no  shelter.  In- 
deed, in  the  admitted  absence  of  exact  knowledge  to  the  con- 
trary, there  are  good  reasons  for  the  belief  that  if  both  sheep 
and  swine  could  be  wintered  under  temperature  conditions 
varying  but  little  from  35°  F.,  except  when  they  are  given 
freedom  for  needed  exercise,  better  results  would  follow 
than  with  simple  protection  from  winter  storms,  provided 
ample  ventilation  always  went  with  the  warmer  housing. 
The  thorough  insulation  nature  has  provided  for  the  bodies 
of  these  animals  makes  it  necessary  that  a  larger  percent  of 
the  heat  produced  in  the  body  must  be  wasted  through 
breathing  and,  for  this  reason,  it  may  be  expected  that  they 
will  thrive  better  in  a  somewhat  colder  air  than  will  cattle, 
but  only  enough  colder  to  remove  the  animal  heat  through 
the  relatively  smaller  surface. 

For  the  reasons  stated,  if  sheep  and  swine  are  housed, 
relatively  larger  air  movement  should  be  continuously 
maintained  through  the  stable,  and  for  the  additional  one 
that  they  breathe  more  air  per  hour  in  proportion  to  their 
weight.  Then  because  the  stables  are  lower,  the  outtakes 
shorter,  and  the  difference  in  temperature  less  and  the  wind 
velocities  as  well,  it  is  necessary  to  provide  relatively  larger 
outtakes  and  intakes.  If  the  minimum  movement  of  air 
through  a  1-foot  outtake  20  feet  high  is  taken  at  one-half  the 


122 


Ventilation. 


value  in  the  table,  page  56,  where  the  temperature  difference 
between  the  air  in  the  flue  and  that  outside  is  10°,  it  will 
be  9,204  cubic  feet  per  hour ;  with  this  rate  of  flow  and  on 
the  basis  of  1,392  cu.  ft.  and  917  cu.  ft.  of  fresh  air  per  hour 
and  per  head  for  swine  and  sheep  respectively  there  should 
be  provided  an  area  of  22  sq.  in.  per  head  for  swine  and  15 
sq.  in.  for  sheep  for  both  outtake  and  intake  flues.  If  the 
outtake  flue  has  a  hight  of  only  15  feet  then  the  number  of 
square  inches  should  be  not  less  than  26  for  swine  and  17 
square  inches  for  sheep  per  head'  for  outtake  and  intake  flues. 
For  16  swine  provided  for,  as  represented  in  the  floor  plan, 

In/aKe  *  North  side  f  Infafte 


Feed  alley 

Bedroom 

\ls 

Bedroom   [j 

Feed  floor 

f 

J  OattaKe 

Feed  floor 

.. 

\^ 

Feed  floor 

> 
Feed  floor 

Bedroom 

Bedroom 

I    D 

r  D 

^    D                          II      t     D 

*Inratew                       ijntoKe  w       ^Intake                   w      Intake 

Fig.  61.— Showing  floor-plan  and   ventilation  of  a  piggery.     The  outtake 
extends  to  within  12  inches  of  the  floor  and  admits  air  on  four  sides. 

Fig.  61,  the  outtake  would  need  to  be  not  less  than  18x18 
inches  inside  with  a  hight  of  20  feet ;  and  20x20  inches  if 
the  hight  is  15  feet.  With  the  outtake  located  centrally  and 
consisting  of  a  single  flue  it  has  the  maximum  efficiency 
and  a  minimum  cost. 

In  the  next  illustration,  Fig.  62,  is  represented  both  floor 
plan  and  elevation  of  a  sheep  stable  with  a  ventilation  sys- 
tem installed  which  is  both  incomplete  and  inadequate.  Ob- 
serve that  the  outtakes  all  terminate  below  the  level  of  the 
ridge  of  the  roof,  which  both  lessens  their  efficiency  and  ren- 
ders them  liable  to  reverse  draft  when  the  wind  is  in  one 
direction.  In  the  80  feet  covered  by  the  10  pens  there  are 


Ventilation  of  Sheep  Stables. 


123 


provided  as  many  outtakes,  each  6x6  inches  and  less  than  15 
feet  high.  The  space  ventilated  should  accommodate  at 
least  50  sheep ;  each  of  the  1 0  outtakes  should  then  have  had 
a  cross-section  of  85  instead  of  36  sq.  in.  as  they  do  possess. 
A  single  central  outtake  28x28  inches,  rising  directly 


Fig.  62.— Showing  floor  plan  and  elevation  of  sheep  stable  in  which  the 
outtakes  are  too  short,  too  small  and  more  numerous  than  needed; 
and  where  no  intakes  have  been  provided,  as  should  have  been. 

through  the  ridge  of  the  roof  20  feet  above  the  stable  floor, 
would  give  much  more  efficient  ventilation.  Two  main  flues 
18x21  inches  placed  one-third  the  distance  from  either  end 
would  be  rather  better  than  a  single  central  flue.  Intakes 
discharging  air  in  at  the  ceiling  and  drawing  it  from  near 
the  ground  level  outside  should  be  distributed  along  each 
side  with  openings  3x12  inches,  20  of  them,  10  on  a  side. 

Ventilation  of  Poultry  Houses. 

So  soon  as  an  attempt  is  made  to  house  any  considerable 
number  of  hens  in  warm  winter  quarters,  not  made  so  with 


124  Ventilation. 

the  aid  of  artificial  heat,  provision  for  ventilation  becomes 
imperative  if  healthful  conditions  are  desired.  It  has  been 
stated  that  a  hen  breathes  about  1.2  cubic  feet  of  air  per 
hour.  In  one  hour  50  hens  would  respire  60  cubic  feet, 
highly  charge  it  with  moisture  and  raise  its  temperature  to 
near  97°.  This  is  2.68  per  cent  of  the  volume  of  air  con- 
tained in  a  room  20x16x7  feet,  the  space  commonly  allotted 
to  this  number  of  birds.  There  is  heat  enough  in  60  cubic 
feet  of  air  at  97°  to  represent 

97X60=5,820  cu.  ft.  raised  1°. 

The  total  air  in  the  room  in  question  is  2,240  cu.  ft.  Sup- 
pose this  has  a  temperature  of  20° ;  this  is  heat  enough  to 
represent,  taking  out  the  60  cu.  ft.  the  hens  have  breathed, 

2,180X20=43,600  cu.  ft.  raised  1°. 
If  we  now  add  these  products  we  have 

43,600+5,820=49,420  cu.  ft.  raised  1°. 
Dividing  this  total  by  the  total  amount  of  air  in  the  room 
we  get 

49,420^-2,240=22°. 

That  is  to  say  the  50  hens,  by  breathing  60  cubic  feet  of 
air  out  of  the  2,240  and  warming  it  to  97°,  letting  it  again 
mix  with  the  balance  in  the  room,  have  raised  the  general 
temperature  from  20°  to  22°.  It  is  clear,  from  these  fig- 
ures that  50  hens  are  unable  to  warm  through  many  degrees 
any  large  volume  of  air. 

Prof.  Gowell,  of  the  Maine  Agricultural  Experiment  Sta- 
tion, recognizing  this  fact  in  a  practical  way,  has  designed 
for  poultry  houses  a  sleeping  chamber,  by  enclosing  the 
roosts  in  a  floored  space  just  under  the  ceiling  and  provid- 
ing the  entire  front  side  of  this  chamber  with  doors  of 
rather  light  canvass,  hinged  at  the  ceiling  so  that  on  cold 
nights  these  may  be  closed  down  for  warmth.  The  size  of 
the  sleeping  chamber  recommended  by  Gowell  is  less  than 
4x4x20  feet  and  the  only  ventilation  provided  is  through  the 
canvass  doors.  It  is  clear  that  the  smaller  volume  of  air 
enclosed  in  the  sleeping  chamber  would  be  maintained  at  a 
higher  temperature  unless  the  air  was  changed  in  it  at  a 


Ventilation  of  Poultry  Houses. 


125 


more  rapid  rate.  Taking  the  capacity  of  the  chamber  at  320 
cubic  feet  and  supposing  that  its  air  is  changed  once  per 
hour  and  replaced  with  that  at  20°,  breathing  alone,  not  al- 
lowing for  loss,  should  maintain  a  temperature  14°  higher 
or  34°,  the  air  of  the  chamber  having  one-seventh  the  vol- 
ume of  the  room  considered  above.  But  if  the  air  in 
the  chamber  is  changed  but  once  per  hour  it  would  contain 
18.75  per  cent  of  air  once  breathed,  instead'  of  3.3  per  cent, 
the  standard  we  have'  assumed  as  possibly  permissible  for 


Fig.  63.— Showing  method  of  ventilating  a  poultry  house.  A  is  sleeping 
chamber  without  floor;  B  is  flue  to  admit  warmed  air  to  sleeping 
chamber  from  cellar  if  one  is  provided;  C  Is  duct  to  admit  air  from 
floor  of  house  to  cellar  to  be  warmed.  If  no  warming  cellar  is  pro- 
vided the  floor  should  be  cemented. 

cows.  We  doubt  if  under  the  conditions  recommended  by 
Gowell  the  air  will  be  changed  oftener  than  once  or  twice 
per  hour  and  such  a  rate  does  not  appear  to  be  sufficient. 
In  view  of  the  considerations  here  presented  we  have  de- 
signed the  poultry  house  represented  in  Fig.  63.  As  shown, 
it  is  16x20x7  feet  and  intended  for  50  hens.  To  guard 
against  low  temperature  a  cellar  is  suggested  under  the 
whole  floor  with  provision  for  air  to  circulate  as  shown  in 
the  drawing,  thus  utilizing  the  ground  heat  for  warming. 
If  a  location  can  be  chosen  which  permits  all  but  the  south 


126  Ventilation. 

front  to  be  largely  in  the  bank  and  a  cement  floor  is  pro- 
vided to  conduct  the  heat  of  the  subsoil  into  the  house 
through  the  general  floor,  this  will  do  much  for  warmth. 
Indeed,  with  four  long  windows  on  the  south,  we  do  not 
hesitate  to  recommend,  for  severe  climates,  placing  the 
chicken  house  in  a  bank  with  the  floor  cemented  and  18  to 
24  inches  below  the  ground  level  in  front.  Such  a  house, 
because  it  can  be  more  thoroughly  ventilated,  will  be  less 
damp  and  more  wholesome. 

For  houses  wholly  above  ground,  the  walls  must  be 
closely  and  warmly  constructed.  A  very  warm  wall  may 
be  made  with  2x8 's  set  3  feet  apart,  covered  with  drop  sid- 
ing outside  and  matched  fencing  inside  or,  what  would  be 
best,  a  light  weight  of  galvanized  iron  nailed  closely  and 
vertically  to  the  studding,  filling  the  spaces  between  the 
studding  compactly  with  dry  fibrous  peat.  The  ceiling 
likewise  should  be  similarly  built  so  that  no  air  may  escape 
through  it.  A  very  warm  ceiling  could  be  made  by  tightly 
packing  the  space  above  very  closely  with  marsh  hay,  rep- 
resented in  Fig.  63.  A  very  warm  poultry  house  can 
be  made  by  using  2x8  studding,  covered  with  drop  sid- 
ing outside  and  only  with  a  light  weight  of  galvanized 
iron  inside,  with  the  space  between  the  studding  closely 
packed  with  fine  marsh  hay  and  treating  the  ceiling  as 
already  described.  The  closely  packed  hay  makes  one  of 
the  best  of  nonconductors,  while  the  metal  makes  the  walls 
and  ceiling  both  air-tight  and  sanitary  in  every  way. 

It  will  be  clear  from  statements  made  on  page  63  that 
where  the'  ventilating  flue  for  poultry  houses  may  rise  16 
feet  above  the  floor  the  cross-section  of  both  outtakes  and 
intakes  should  provide  some  4  square  inches  per  bird,  or 
at  the  rate  of  200  square  inches  for  each'  50  hens  or  their 
equivalent. 


INDEX. 


Abbot,  Dr.  C.  <i..  Idler.  s4:  relative 
Intensity  of  skylight,  84;  best  window 
exposure.  S5:  form  of  \vindo\v  for  max- 

'  iinuni  liyhtiny.  S5:  comparativ. 
amount  of  liyht  from  sky  and  sun.  s.~> 

Air.  amount  breathed  l).v  diH'erent  an- 
imals. 9:  amount  Inadequate  without 
definite  provision.  19:  amount  use<i  in 
combustion,  v  composit  ion.  of  pure. 
13,— of  once  l)reatlied.  14.  (is.  ofstable. 

?o:  continuous  flow  necessary,  K:cost 

of  warmintr.  »>•'>:  density, Ofpure  at  dif- 
ferent lemperaturesy.s.  of  respired  at 

different  temperatures.  68<    difference 

Of, demonstrated. 60:  experimental  de- 
monstration of  changes  in  respired. 
13,  15.  16.  69:  formulas  for  computing 
flow  Of,  47,  48,  55;  graphic  representa- 
tion  of  amount  breatlied.  10:  once 
breathed  loses  in  food  value.  11:  rale 
•of  flow  in  outtakes.  56.  57.  59.  611.  t!6. 
due  to  wind  pressure.  47.  57.  due  to 

wind  suction.  4s.  ;>:.  due  to  difference 
In  temperature,  53.  56i  56,  due  to  hu- 
midity, til:  specific  heat  of.tr.:  volume 
of.  required  for  dwellings,  96,  41, 90, 

for  Stables,  41.42.4:!.  62.  — for  cows  and 
horses.  42.  43.  120,— for  sheep  and 
swine.  43.  121. —for  poultry.  41.  42.  63. 
120.— breatlied  per  hour.  10. 
Armsby.  Dr.  II.  I'.,  amount  of  moisture 
transpired  by  steer.  34. 

Hlood.  aeration  of.  6:  corpuscle-,.!),  ex- 
tent of  .surface.  7.— function  of.  6: 
movement  of,  7. 

Carbon  dioxide,  amount  in  air,  13,  14,— 
in  stable  air.  37.  40.  70:  as  index  of  air 
purity.  36:  how  removed  from  system, 
6. 

Camel ly.  standard  of  air  purity,  36. 

Clarke,  composition  of  air,  13. 

Cow.  air  breathed  per  hour.  9.  10:  cro.ss- 
section  of  ventilating  flue  for.  42.  120: 
heat  produced  by.  64:  moisture  trans- 
pired by.  34:  ventilation  experiment 
with.  28.  37.  38,  70:  ventilation  of 
stables  for.  109-120. 

Colin,  amount  of  air  respired  by  differ- 
ent animals.  9. 

De  Chaumont.  standard  of  air  purity 
for  man,  96:  volume  of  air  movement 

for  man.  36. 
Diseases,    susceptibility  to  contagious. 

»-4,  89. 


Dwelling,  ventilation  of,  88,—  by  fire- 
place-,. ss.  <».")  by  stoves.  !»1.  when 
wai-med  with  hot  air.  93.  when  warm- 
ed with  steam  01-  hot  water.  73.  loo. 

l-'ireplace.  ventilation  by.  ss.  ;»5. 

Florham  I'ark  stables.  .">3.  59.  t>o. 

I  'I  lie-,  flow  of  air  in.  t  heoret  ical.  56.  57.  — 
methods  of  computing.  52.  .').').—  ob- 
served. 59.  T.O.  66:  for  houses.  ;»2.  97,  98, 
101:  for  school-houses.  103.  KH5:  for 
stables.  107.  10!'.  Ill  IIS.  123.  12f.:  hiylit. 
r,0:  si/e.  liii.  i>:5.  120.  121.  12f>:  capa.-ity 
of.  rui.  57,  H3.  122. 


l.    <;.    M..    ventilation  of   p;>ultry 
houses.  124. 

llaldane.  standard  of  air  purity,  36. 

Heat,  amount  yiven  oft'  by  cow.  tU:  mo- 
tive power  in  ventilation.  f>2.  .">t>.  i>7: 
utili/.ed  in  ventilation.  71:  speciti.-,.  tki. 

Beating,  poultry  houses  with  sub-cel- 
lar. 12.~>:  rural  .school-houses.  103.  106: 
with  tii-e|)laces.  ss.  ;»;,:  with  hot-air 
furnaces.  !hi:  with  steam  and  hot 
water,  loo-,  with  stoves.  91.  106. 

Hen.  air  breathed  p,.r  hour.  9.  renuired 
in  ventilation.  41.  42.  warmed  by 
breathing,  124:  moisture  thrown  off 
by.  2*:  outtakes  and  intakes  for.  12ti. 

l  loi-se.  air  breathed  per  hour,  9,  10.  —  vol- 
ume of.  for  <rood  ventilation.  41.42: 
area  of  outtakes  and  intakes  for.  120. 

House,  warmiiiir  and  ventilation.  8S-  102: 
type  of.  readily  warmed  and  ven- 
tilated. 102:  ventilated,  with  fire- 
place. ss  «.(.->.  with  hot-air  furnaces. 
96.—  when  heated  with  steam  or  hot 
water.  100.—  with  stoves.  91. 

Humidity,  as  motive  power  in  ventila- 
tion. 60-63:  of  air  in  U.S.,  34:  of  re- 
spired air.  14.  32. 

Intakes.  49.  72.74.  75:  for  dairy  stables. 
59.  72.  75.  111-114.  117.118:  for  base- 
ment stables,  118:  for  dwellings, 
92.101:  for  piggeries,  122;  for  poultry 

houses.  125:  for  schoolhouses.  103.  105. 
106:  sixe.  120.  122.  123.126:  types  of.  109; 
velocity  of  flow  through.  59. 

Jordan.  Dr.  W.  II..  composition  of  stable 
aii-.  37,  73:  heat  Driven  off  by  cow.  64. 

Ionian.  K.  L..  air  movement  through 
stable.  65:  temperature  of  stable.  65. 

Lamp,  oil  burned  by.  20.  90:  ventilation 
experiments  with.  20-23,  27. 


128 


Index. 


Light.  Abbot,  views  and  observations 
on,  84;  amount  admitted  by  windows, 
85,  86,  87;  cannot  be  depended  upon 
for  complete  destruction  of  germs, 
83;  destroyer  of  disease  germs,  81:  for 
dwellings  and  stables,  78;  from  whole 
sky  compared  with  sun,  85;  most  in- 
tense from  south  sky,  85;  Weinzirl.  on 
destruction  of  disease  germs  by,  82. 

Magnesium  ribbon,  combustion  in  pure 
and  breathed  air,  12.  13. 

Man,  air  breathed  per  hour,  9.  10,— re- 
quired in  ventilation,  41, 42,— standard 
of  purity  for.  36;  amount  of  moisture 
transpired  by,  33. 

Moisture,  amount  transpired  by  man. 
32,— by  cow,  33,— amount  of  air  re- 
quired to  remove,  33,  34:  as  motive 
power  in  ventilation,  60;  effect  on  air 
density,  68;  in  respired  air,  14. 

Nitrogen,  amount  in  air,  13,  14. 

Offices,  ventilating.  73,  75. 

Outtake.  cross-section  for.  120.  121.  126; 
defective  shelter  for.  50.  51.  52:  dimen- 
sions, for  cows  and  horses.  62.  120, — for 
swine  and  sheep.  63,  121.— for  poultry, 
63.  126:  for  horses,  92.  97.  100;  for 
school-houses.  102.  106:  for  stables,  74, 
107,  109,  111-117,  122,  123,  125;  hight  of, 
53,  56,  63,  126:  location  of.  74;  essential 
characteristics  of.  107;  proper  termi- 
nation for,  53;  table  of  rate  of  flow 
through,  fit?.  57.  59.  (50.  66. 

Oxygen,  amount  consumed  by  man.  at 
different  temperatures.  77:  amount  in 
air.  13.  14;  effects  of  deficiency  of.  24: 
required  in  combustion,  1,  8. 

Pigs,  air  breathed  per  hour.  9, 10,— move- 
ment for  ventilation,  41,  43;  venti- 
lation for.  63.  121,  123. 

Poultry,  ventilation  for.  63.  125. 

Pressure,  due  to  difference  in  temper- 
ature, 52.  55:  due  to  humidity.  60;  due 
to  wind  impact.  47:  due  to  wind  suc- 
tion, 48. 

School-house,  warming  and  ventilation 
of.  73,  103.  106. 

Seguin.  moisture  transpired  by  man.  33. 

Shaw.  W.  N..  velocity  of  air  in  flues  due 
to  different  wind  velocities,  measured 
by.  58. 

Sheep,  air  breathed  per  hour,  9,  10, -re- 
quired for  ventilation,  41.  43;  ventila- 
tion for.  121.  124. 

Shelters  for  outtakes.  50—53. 


Stables,  air  movement  to  prevent  mois- 
ture condensation.  33.34:  composition 
of  air  in.  37,  39.  70;  lighting  for.  79; 
maximum  lighting  effect  for.  86;  per- 
meability of  walls  to  air,  37.  38;  ven- 
tilation of,  107;  windows  for,  80,  81, 
86,  87. 

Stoves,  as  ventilators,  91,  106. 

Temperature,  best  for  room  and  stable' 
76;  computed  maintenance  for  sta- 
bles. 65;  observed  in  stables.  66,  70; 
difference  of,  in  ventilation,  56.  58. 

Tobiri  tubes.  75. 

Twombly,  H.  McK.,  stables  of,  53,  59. 

Ventilation,  and  maintenance  of  tem- 
perature 64:  demonstration  chamber 
for,  20:  experiments,  with  cows,  28. 38, 
66,  70.— with  hens,  22,  23.—  with  lamp, 
20,  23:  extra  heat  needed  for  not  great, 
67;  flues,  improper  installation  of, 
50,— shelter  for.  51-53:  for  sheep  and 
swine. 120;  for  poultry.  123;  full  utili- 
zation of  waste  heat  in  securing.  67; 
maintenance  of  temperature  to  in- 
crease, 71 ;  mean  effective  difference  in 
temperature  for.  in  houses.  58.— in 
stables.  58;  motive  power  in.  wind  im- 
pact. 47.— wind  suction,  48.— differ- 
ence in  temperature,  52. 55.— humidity 
of  air,  60;  mean  effective  wind  veloc- 
ity for,  58;  mean  effective  difference 
in  temperature  for,  in  houses.  58.— 
in  stables.  58:  need  of  increasing. 
18,  88:  of  body  tissues.  3:  of  dairy 
stables.  109:  of  houses  already 
built,  90:  of  new  and  remodeled 
houses,  94:  of  school-houses,  102;  of 
stables.  107:  power  required  in,  46; 
practice  of,  76:  principles  of.  45; 
principles  of  construction  for.  73; 
problem  of.  stated,  41:  serious  effects 
follow  insufficient.  24:  through  fire- 
place. 88;  through  stoves.  91,  106. 

Weinzirl.  Dr.  John,  efficiency  of  light 
as  a  germicide.  s± 

Wind,  action  in  producing  ventilation, 
49:  flow,  due  to  impact  of,  47.  57. — due 
to  suet  ion  a  1  effect  of.  48.  57:  mean  ef- 
fective velocity  of.  58. — may  be  very 
small  or  nil.  62:  pressure  of.  47:  suc- 
tional  effect  of.  48. 

Windows,  efficiency  of.  86-88:  faulty 
arrangement  of.  80:  form  and  expos- 
ure of  for  maximm  lighting.  81:  num- 
ber, size  and  exposure,  79:  south  ex- 
posure best. 


THE  SOIL 

By  F.  H.  KING 

Professor  of  Agricultural  Physics  in  the  University  of  Wisconsin.  1888-1901 ; 
Chief  of  the  Division  of  Soil  Management,  U.  S.  Department  of  Agricul- 
ture, 1901-1904. 

Author  of  "Irrigation  and  Drainage,"  1899 ;  "Physics  of  Agriculture,"  1901 ; 
"Tillage,  Its  Philosophy  and  Practice,"  "The  Necessity  and  Practice  of 
Drainage"  in  Cyclopedia  of  American  Agriculture,  1907;  "Drainage"  and 
"Irrigation,"  In  The  Standard  Cyclopedia  of  Modern  Agriculture,  (British) 
1908. 

303  pages,  7x5  inches,  45  illustrations.— $1.68  prepaid. 


CONTENTS 

Introduction    1-  26 

The  Nature,   Functions,   Origin  and  Wasting  of   Soils 27-69 

Texture.    Composition   and    Kinds   of    Soils 70-106 

Nitrogen  of  the  Soil 107-184 

Capillarity,  Solution,  Diffusion  and  Osmosis 135-153 

Soil   Water    154-183 

Conservation    of   Soil   Moisture 184-206 

The  Distribution   of  Roots  in  the  Soil 207-217 

Soil    Temperature     218-238 

The  Relation  of  Air  to  Soil 239-252 

Farm    Drainage    253-267 

Irrigation     268-275 

Physical  Effects  of  Tillage  and   Fertilizers 276-294 


"I  consider  it  a  most  desirable  addition  to  our  agricultural  literature,  and  a 
distinct  advance  over  previous  treatises  on  the  same  subject,  not  only  for 
popular  use,  but  also  for  students  and  specialists."  *  *  * 

Dr.  E.  W.  Hllgard,  Director  Calif.  State  Agr.  Exp.  Station. 

"For  practicability  and  entertaining  power  combined  this  work  is  at  the  head 
of  Its  class." — The  Boston  Traveller. 

"The  manual  is  brief,  accurate,  comprehensive  and  hits  the  practical  point 
every  time." — Independent. 

"It  Is  a  book  which  progressive  farmers  will  come  to  regard  as  one  of  the 
essential  implements  of  farm  life." — Boston  Daily  Advertiser. 

"The  great  point  about  the  book,  In  our  opinion,  is  Its  thorough  practical 
nature.  Personally  the  writer  is  acquainted  with  probably  all  modern  works 
on  this  vitally  important  question  *  *  *  ;  but  we  certainly  never  derived 
so  real  benefit  from  the  perusal  of  any  two,  nay,  even  three  or  four  works  of 
this  character,  as  from  the  one  now  under  consideration." — E.  Kemp  Toogood, 
F.  R.  H.  S.  in  Royal  Cornwall  Gazette. 


IRRIGATION  AND  DRAINAGE 

By  F.  H.  KING 

Professor  of  Agricultural  Physics  in  the  University  of  Wisconsin,  1888-1901 ; 
Chief  of  the  Division  of  Soil  Management,  U.  S.  Department  of  Agriculture 
1901-1904. 

Author    of    "The    Soil,"    1895 ;    "Physics    of    Agriculture,"    1901  ;    "Tillage,    Its 
Philosophy    and   Practice",    "The   Necessity    and    Practice   of    Drainage",    in 
Cyclopedia   of  American   Agriculture,    1907 ;    "Drainage"   and   "Irrigation   in 
The  Standard  Cyclopedia  of  Modern  Agriculture,   (British),  1908. 
502  pages,   7x5   inches,   163   illustrations. — $1.66   prepaid. 


CONTENTS 

Introduction     1-  65 

PART  I.     IRRIGATION  CULTURE 

The  Extent  and  Geographic  Range  of  Irrigation 66-  90 

The  Conditions  which  make  Irrigation  Imperative,  Desirable,  or  Neces- 
sary           91-116 

The  Extent  to  which  Tillage  may  take  the  Place  of  Irrigation 117-170 

The  Increase  of  Yield  Due  to  Irrigation  in  Humid  Climates 171-15)5 

Amount  and  Measurement  of  Water  for  Irrigation 196-221 

Frequency,  Amount  and  Measurement  of  Water  for  Single  Irrigations. .   222-247 

Character  of  Water  for  Irrigation 248-2H8 

Alkali  Lands 269-289 

Supplying  Water  for  Irrigation ". .   290-328 

Methods  of  Applying  Water  in   Irrigation 329-402 

Sewage   Irrigation    .- 403-414 

PART   II.      FARM    DRAINAGE 

Principles  of  Drainage 415^466 

Practical  Details  of  Underdrainage 467-492 

"To  the  ordinary  farmer  the  title  of  this  book  is  somewhat  misleading.  If 
he  is  not  hi  an  irrigating  district,  and  has  no  wet  lands,  he  will  at  once  con- 
clude, on  seeing  the  title,  that  the  subjects  treated  in  the  book  do  not  concern 
him  to  the  extent  of  $1.50.  If,  however,  by  chance  he  has  the  opportunity  of 
reading  the  book  he  will  change  his  opinion.  The  proper  amount  of  water 
available  at  the  right  time  is  essential  to  successful  or  profitable  farming  in  any 
country,  and,  therefore,  Professor  King  opens  his  books  with  some  general  re- 
marks on  the  importance  of  water ;  on  the  texture  of  the  soil  necessary  to  con- 
serve the  moisture  ;  and  follows  it  up  with  the  report  of  some  experiments  show- 
ing the  amount  of  water  used  by  plants,  which  will  be  a  surprise  to  the  farmers 
who  have  not  investigated  the  subject.  The  method  by  which  the  water  is  ob- 
tained by  plants  and  exhaled ;  the  remarkable  way  in  which  the  plants  them- 
selves control  the  demand,  economize  water,  so  to  speak ;  the  mechanism  by 
which  the  roots  get  hold  of  the  moisture :  the  extent  of  the  root  surface ;  all 
these  are  treated  in  a  wonderfully  interesting  way  in  this  book,  and  are  of  all- 
absorbing  interest  to  the  man  who  is  farming  for  dear  life,  and,  if  he  is  properly 
awake  to  the  importance  of  the  subject,  will  prove  as  interesting  as  a  novel 
We  regard  it  as  one  of  the  most  valuable  contributions  made  to  the 
science  of  agriculture  in  recent  years." — Wallaces'  Farmer. 

"But  although  the  author  travels  far  and  wide  in  search  of  examples  and  re- 
sults in  illustration  of  the  principles  which  he  advances,  and  so  far  introduces 
matter  which  is  of  great  importance  in  the  discussion  of  irrigation  proper,  yet 
the  bulk  of  what  he  has  written  is  full  of  instruction  of  the  most  practical 
character  for  the  rent-paying  farmer." — Manchester  (England)  Guardian. 


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